This is an archive of past discussions about Planet Nine. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.
In the article it states that Planet Nine hasn't been named yet but is called "George" another name for the planet is "Mieko" or "Meiko". Could this possibly be it's real name? Fdmjiv (talk) 22:28, 17 September 2016 (UTC) If you find that name as one name that Planet Nine is being called please tell me on my talk page. Thanks! Fdmjiv (talk) 22:32, 17 September 2016 (UTC)
Amusingly, the IAU's Naming of Astronomical Objects page does not seem to mention new full planets in our solar system. However, assuming the process is at least as elaborate as for dwarf and minor planets:
First the planet has to be properly discovered.
Then the orbit must be determined with some accuracy.
Then the discoverer (person or team) has the privilege of making the first formal name suggestion.
New paper. The interaction of Planet Nine with a preexisting disk produces a spheroidal distribution of objects with semimajor axes near 1200 AU due to interactions with its mean-motion resonances, an inclined disk between 1500 AU and 3000 AU and a warped disk beyond this. Agmartin (talk) 16:45, 29 September 2016 (UTC)
Generation of Highly Inclined Trans-Neptunian Objects by Planet Nine
High inclination objects acquire their unusual orbits via Kozai-Lidov cycles driven by Planet Nine and close encounters with Neptune. Perihelion is raised then later lowered while at high inclination. Encounters with Neptune can then lower semimajor axis below 100 AU. High inclination objects in two groups one with perihelion of 5 - 35 AU and dinclinations up to 100 degrees the other with perihelion around 10 AU and inclinations near 150 degrees. There is also a gap between these groups and no common plane like with Drac and Niku. Agmartin (talk) 21:00, 18 October 2016 (UTC)
The point to note here, I think, is that in earlier simulations B&B had modelled all the giant planets as a single disk, so they couldn't use that model to simulate objects which come close to Neptune. In this new model, the giant planets are modelled as separate objects thus allowing them to model the trajectories of high inclination objects that come closer to Neptune. J mareeswaran (talk) 15:52, 20 October 2016 (UTC)
L91 never comes closer to the sun than 50 astronomical units (AU), or 50 times the Earth-sun distance. From there, it slowly crawls all the way out to 1,430 AU. This means it has a more elongated orbit than Sedna, another distant Pluto-sized object, whose closest approach is 76 AU and whose estimated far point reaches 937 AU.
In a second paper, Brown and Batygin (2016) showing a possible secondary longitude of perihelion clustering 180 degrees away from main longitude of perihelion clustering for some simulations. This smaller population secondary longitude of perihelion clustering should generally take place at lower semi-major axes than most of the main clustering and it appears 2013 FT28 is in this secondary longitude of perihelion clustering.J mareeswaran (talk) 06:52, 18 September 2016 (UTC)
objects with q > 35 and a > 150 AU have argument of perihelion between 290 and 40 degrees, significant and six sigma level
objects with q < 35 and a > 200 AU have argument of perihelion largely clustered in opposite direction (these are mostly objects with perihelia < 25 AU including some crossing Jupiter's orbit)
for objects with q > 35 and a > 150 AU longitude of perihelion is correlated with argument of perihelion, those with long peri 0 - 120 degrees have arg peri 280 - 360 degrees, those with long peri 180 - 340 have arg peri 0 - 40, significance of correlation 99.99%
their analysis including observational biases and stability of the finds the clustering of longitude of perihelion is likely real but marginal (page 17)
71% of objects with q > 40 and a > 150 AU should have 50 < q < 75, odds of their survey finding three without one in this range ~2%, including other surveys assuming same biases (unlikely since theirs only followed up on objects at greater than 50 AU) odds 6x10^-11 or seven sigma Agmartin (talk) 21:12, 1 September 2016 (UTC)
"objects with q < 35 and a > 200 AU have argument of perihelion largely clustered in opposite direction" Five of these 8 are the perpendicular objects noted in the original paper the remaining three probably aren't significant, which probably explains why they dropped the mention of them in the abstract of the latest version on arxiv. Agmartin (talk) 21:34, 15 September 2016 (UTC)
It works for me. Could it be any larger? I wish we could show an inner circle of Neptune. I'm not against cropping the outer orbit of 2014 FE72 for space reasons. The main question is whether we want to follow the "new extreme objects" coloring approach, or this of just showing all the objects. It looks like 2007 TG422 was missed on the [8] graphic I tried to trace. Tom Ruen (talk) 15:09, 13 September 2016 (UTC)
I added the cropped one to the article above the table. It would also be great if each object was shown in its current position around the orbit. Finally, what about the other 3 objects above not included? I see semimajor axis less than 250 AU. 2014 SS349 (a=142<250 AU), 2013 UH15, (a=172<250 AU), 2013 FS28, (a=196<250 AU). Tom Ruen (talk) 21:14, 13 September 2016 (UTC)
p.s. I compared the original one with cropped. It looks like the view direction (north-to-south or south-to-north is reverse between the two. Perhaps this should be clarified which one is which. Tom Ruen (talk) 22:55, 13 September 2016 (UTC)
Honestly, Tomruen, it would probably be simpler and overall more useful to take your SVG attempt and file a request at Commons:Commons:Graphic Lab/Illustration workshop asking someone to pretty-please fix it (and to insert the Sun in the image). SVGs are always best for these sorts of images because they scale, are small, and can easily be translated when necessary. I tried to fix it, but my Inkscape-fu is zero and the code is too complex for manual text editing. — Huntster (t@c)00:55, 14 September 2016 (UTC)
Agreed SVG are better. Part of the problem is the traced image includes a slightly different subset of objects. ALSO I think the perspectives are a bit different, AND probably even the P9 representative orbit is somewhat different. So anyway, I'd trace a SVG from Agmartin's image if that's the set of objects we want to represent. Tom Ruen (talk) 02:04, 14 September 2016 (UTC)
I don't think tracing (of any variety) is the best way to go, if only for the sake of accuracy. Additionally, re-scaling/retooling the image every time a new object gets added would be annoying. When I made File:EN131090 with text.png, I used MATLAB to plug in the actual coordinates, which allowed for a very accurate reproduction. Maybe we should do the same for this; not only would it give accurate orbits, it would also be (relatively) easy to add new objects (plus it would be easy to add/subtract orbits to see what it would look like). It wouldn't be an SVG, but it would still look decent at high resolution. Primefac (talk) 02:24, 14 September 2016 (UTC)
Sure, I agree best for a orbit renderer to compute ellipse objects directly. It's just a little tricky to take a certain perspective and determine the 2D ellipse for each projected 3D orbit. Tom Ruen (talk) 04:54, 14 September 2016 (UTC)
The orbits I've plotted (using excel) are the ellipses as they would be seen if all of the objects were coplanar and using the data from the table. That's probably why they don't look quite like the other images, and why the sun looks kind of square. It shows the alignment and relative sizes of the orbits, which is what I expect those reading the article would be most interested in seeing. Agmartin (talk) 18:04, 14 September 2016 (UTC)
Incidentally, I looked back and saw this view [9] from [10] which is nice for showing the current positions of the bodies, and the ellipse brightness fades, so you can tell the direction of motion. It would be nice to do something like this in SVG. Tom Ruen (talk) 23:15, 14 September 2016 (UTC)
p.s. This article also talks of "A seventh distant object, spotted by the Outer Solar System Origins Survey, was discussed by Michele Bannister", sourced here [11], listed there as uo3L91 is NOT included in the new list of objects. I tried overlaying some images, and its orbit is clearly unique from the new 3 ones listed, AND its apogee is much further than the 3 other objects listed at the top of this section, excluded by semimajor axis closer than 250AU. Anyway, it seems strange this object described in a March public lecture has not been publicly defined! Is there ANYTHING on that mystery object? OH, I see an article exists uo3L91, but largely unsourced. Tom Ruen (talk) 23:04, 14 September 2016 (UTC)
The DPS-EPSC abstracts list a talk about this object on October 16, I expect the data for it and other objects will show up at the MPC site around then. When I did a fit for this object I found a perihelion of ~50 AU and a semimajor axis of ~750 AU. Agmartin (talk) 16:32, 15 September 2016 (UTC)
It looks to be a transitional member of the group- it's pretty close to the Nine group to be a coincidence. However, it seems Neptune has started to have an effect on it as well. exoplanetaryscience (talk) 23:27, 11 October 2016 (UTC)
'So the strategy in the race is now largely a matter of reducing the search area by eliminating theoretical possibilities. In an as-yet unpublished set of about 100 new high-resolution computer simulations, Batygin says he and Brown have narrowed down Planet Nine's location to a roughly 600- to 800-square degree patch of sky.'
The orbital diagram three had a different orientation for P9, but Sedna and others matched, so I added L91 orbit onto the crappy low-res image until we can get something better. There were also a couple of other unlabeled smaller gray orbits there ignored. Tom Ruen (talk) 20:37, 26 October 2016 (UTC)
"Batygin and Brown suggest that it may be a primordial giant planet core..."
This may come across as some to suggest it is the core only; a super-earth rather than an ice giant like Uranus or Neptune. Perhaps some rewording is in order? 134340Goat (talk) 20:09, 25 October 2016 (UTC)
Part of the reason I ask is multiple sources assume the planet is a mega-Earth, other sources assume ice giant. It would be helpful if the opening paragraphs stated what Brown and Batygin's paper say 134340Goat (talk) 23:21, 30 October 2016 (UTC)
I doubt if the B&B's paper says anything about composition. At this point we only know the approximate estimated mass. Other details are not clear.J mareeswaran (talk) 02:41, 31 October 2016 (UTC)
Neptune size comparison
Nice picture comparing size to Earth, but is there one comparing its likely size to Neptune? I believe the most likely size for P9 is about 30,000-35,000 km in diameter. Is there something comparing it to Neptune, possibly Earth AND Neptune? I feel it would be beneficial to many readers. 72.231.228.215 (talk) 06:55, 19 November 2016 (UTC)
For Neptune, Earth size likely comparison, this picture may do, Neptune, Earth size comparison 2 the file contains more. Having Planet Nine hypothetical radius as (13,000 to 26,000 km), and for Neptune (24,622±19 km), either one may be assumed smaller than the other. The only solid evidence we have for P9 existance is ″improbable orbital configuration of the group″ on the left side of the Sun,(see the above graphs in this page); a mass approximately 6×1025 kg. arround the red colored orbit. This mass may be provided by more than one single planet, who knows!. --Mpj7 (talk) 14:28, 19 November 2016 (UTC)
A second video, this one is an excerpt from the Adler Planetarium full length sky show on Planet Nine, it includes an animation from a simulation of the extreme KBOs as influenced by Planet Nine. Agmartin (talk) 20:57, 3 December 2016 (UTC)
What is calculated about the planet's hill sphere? Given its eccentricity stretching hundreds of AU, it may be prudent for a graph to be made, perhaps a line separating perihelon to aphelion's hill sphere? It must be simply enormous compared to Neptune's. — Preceding unsigned comment added by 107.77.223.34 (talk) 00:16, 6 January 2017 (UTC)
5.2 An alternate interpretation of the results: As shown in Figure 4, for example, the time-averaged measure of clustering in the KBO arguments of perihelion, is almost always smaller than the present day value, In other words, sustained clustering that matches the present-day value is exceptionally diffcult to obtain. The fact that it is so challenging could be viewed as evidence against the planet's existence. Agmartin (talk) 20:40, 23 December 2016 (UTC)
Could this be an artifact of observational bias? When Planet Nine is at aphelion (probable), are we more likely to see the clustered objects, and not see the non-clustered ones? At aphelion aren't all the objects in low integer ratio mean motion resonances most likely to be at perihelion? JehochmanTalk14:47, 25 January 2017 (UTC)
Aphelion isn't a single time, but a large fraction of its orbit. I don't know how many fewer would be close during the relatively shorter perihelion. All the objects observed are near perihelion because they would be too dim to view at any other time, so there must be hundreds of more similar bodies we can't see that follow the same orbits, or not if there is no real pattern and no P9. It would certainly be better to have 100 confirming objects than less than 10, but maybe the ones we see now are all we're capable of seeing. Tom Ruen (talk) 11:03, 26 January 2017 (UTC)
In Brown and Batygin http://adsabs.harvard.edu/abs/2016ApJ...824L..23B they found a low percentage of simulations matched all of their constraints (see figure 2) so maybe the extreme TNO population isn't quite as well aligned as they appear. This might mean there is some observational biases, though I doubt it is due to P9 being near aphelion since some of the objects probably have periods less than 1/3 of P9's. There is still the arrangement of the perpendicular objects objects which probably don't have the same observational biases since they are more scattered in the sky than the first six of the ETNO's. Some other effect may be missing, perhaps their upcoming paper will reveal what it is. Agmartin (talk) 22:11, 27 January 2017 (UTC)
I finally got around to adding orbit paths to my astronomy software, and updated the orbits for the TNOs, all 9 in main table except uo3L91 which I didn't have full parameters. I picked a view location and orientation similar to the one given in the article (P9 in green). The first thing that struck me, of course, was to see how the current positions are all so close to perihelion, so statistically we know there must be hundreds of additional objects (whether they agree with these positions or not), but too far away (so far) to be seen. I added a close up image, top-right, with the 9 bodies labeled. I added a third view, from earth now, with P9 and coincidentally 5 of 9 of the TNOs. I included current distances there and magnitude estimates, and 3 are similar to what P9 might be, 23-24 magnitude. And a 4th image from 6000BC (When P9 maybe near perihelion), with 4 objects clustered in Virgo with magnitudes 33 to 36, undetectable! Tom Ruen (talk) 13:37, 30 December 2016 (UTC)
View from above solar system
Close up view from above solar system
View from earth now
View from earth in 6000BC
Thanks, I hadn't noticed before how clustered in the sky the first six objects found were. Some of that is because the alignment results in them being brightest in that part of the sky, but I wonder how much is observer bias. If extreme TNO's are often lost because the assumed orbits based on short arcs are wrong (I think this is called ephemeris bias) perhaps that location is good for following up several months later so they aren't lost before the second year. Agmartin (talk) 18:08, 30 December 2016 (UTC)
I decided to add the current-position graphics to the article, along with the wide view one with all the orbits. The orientation is slightly different, and its missing the 10th one without full parameters, but I think it's helpful. Tom Ruen (talk) 14:31, 11 January 2017 (UTC)
Here's one more simulation, adding the 5 high inclination orbits, all of them now within the orbit of Uranus. The view location over 1 million AUs away, so minimal depth perception. (I suppose I should try a 3D image for red-blue glasses!) Tom Ruen (talk) 17:57, 16 January 2017 (UTC)
Here's a rectangular sky plot of the current sky positions of most of 9 TNO in magenta (aphelion>250au), 10 TNOs in yellow (ap>150au), and 5 high inclination bodies in blue. A nice clustering near Cetuss! Tom Ruen (talk) 22:55, 27 January 2017 (UTC)
The longitude of perihelion I determined from the graphic in the SETI talk video was only off by 0.3 degrees. Pats self on back. :-P Agmartin (talk) 23:56, 6 April 2017 (UTC)
lucky object 'Faint, uncharacterized objects are very difficult to recover and track: they are only imaged if they serendipitously fall within the wide MegaPrime field of view during observations to refine the orbits of the brighter characterized TNOs. The four months of serendipitous observations of 2013 SY99 in 2013 implied that it was plausibly on anactively scattering orbit. Agmartin (talk) 01:24, 7 April 2017 (UTC)
Consequences of a Distant Massive Planet on the Large Semi-major Axis Trans-Neptunian Objects
Here's a plot of orbits and current positions the 10 TNOs with 250 au > a > 150 au and q > 30 au, with a hypothetical Planet 9 in greenSide view of 10 TNOs with 250 au > a > 150 au and q > 30 au, with horizontal hypothetical Planet 9 in green
Simulated the orbits of clones of the observed objects rather than starting from a disk interacting with Neptune. Did not begin with objects in resonances since "resonance confinement is not the proposed mechanism for ω bar shepherding". Found:
the perihelia and inclinations oscillated
objects entered high perihelion and high inclination (sometimes retrograde) orbits
some shepherding of longitude of perihelion but clustering was not dominant feature after 2 Myr of simulation
observed clustering of argument of perihelion and ascending node not reproduced
much of population too high perihelia and inclination to be observed
estimate of mass need to reproduce observed population tens of earth masses
initial solid mass required 100s - 1000s earth masses
simulations produce high inclination high semimajor axis objects that are not observe (did they miss the 5 pointed out in Batygin & Brown?) Agmartin (talk) 19:49, 20 October 2016 (UTC)
My guess is that the reason for the difference between their results and B&B is the objects are not started in resonances (though some clones spend time in resonances). I did see another paper showing longitude of perihelion confinement without resonances. Agmartin (talk) 19:49, 20 October 2016 (UTC)
It looks like a peer review of B&B's hypothesis by doing their own simulations. Their conclusion seems to be that:
They are sceptical of the existence of p9 because it requires more such objects & they consider that to violate the current theories of evolution of planetesimal disk
Their explanation is that the alignment in ETNOs is a co-incidence that will go away as more objects are discovered.
IMO Bannister et Al's objections to P9 sounds very similar to B&B's objections to Madigan's self-gravitating disk. But with another paper speculating that existence of P9 implies a spheroidal disk of inner Oort cloud objects, & Bannister acknowledges that this possibility exists but dismiss it as unlikely.
My takeaway from this is that if this observed clustering is real & permanent then it implies either a massive self-gravitating disk or a spheroidal cloud that is generated by P9. (Which can supply or act as a source for these distant objects that exhibit the observed clustering characteristics. J mareeswaran (talk) 07:41, 21 October 2016 (UTC)
A previous paper by this group of authors that began with of a simulated disk of objects that are scattered outward has been updated with plot of argument of perihelion, ascending node, and longitude of perihelion vs semimajor axis (figure 5) that also shows no alignment. https://arxiv.org/pdf/1605.06575v2.pdfAgmartin (talk) 20:55, 26 November 2016 (UTC)
Looking at some of the plots available via the link on page 6 of the Shankman paper the objects that show alignment tend to have the alignment broken when they come back into Neptune's reach. So maybe what's needed to preserve the alignment may be some mechanism to lift the perihelia of the objects before Planet Nine takes control of their dynamics, for example, if their perihelia are lifted by a Kozai resonance while in resonance with Neptune then they might stay far enough beyond Neptune's influence when the perihelion returns to its low values. If they were in the Kozai resonance with the argument of perihelion centered at 270 degrees they could move toward 360 degrees as the perihelia were lifted, and possibly be near the 320 degrees that these values cluster around when dynamical control shifts to Planet Nine. How this previous lifting would happen without Planet Nine breaking the either resonance first I don't know, unless it occurs before Planet Nine entered its current orbit. Agmartin (talk) 21:59, 26 November 2016 (UTC)
That video simulation certainly does show much "shepharding". But Batygin ran thousands of simulations, so something needs explaining. Tom Ruen (talk) 06:35, 12 January 2017 (UTC)
Some things that aren't included yet in the simulations I've read about; Neptune's migration, Planet Nine's migration during that period, the effect of the galactic tide on P9's orbit. If P9's orbit is changing or has changed it might affect resonant objects, for example, they might be captured into resonances, like Pluto, instead of just sticking like 2015 RR345. Agmartin (talk) 22:15, 12 January 2017 (UTC)
I was giving this paper a second look and noticed an interesting coincidence, the Sedna clones' perihelia start crossing the orbits of the planets after ~700 Myrs, about the time of the Late Heavy Bombardment. Agmartin (talk) 00:59, 28 April 2017 (UTC)
Observational bias and the clustering of distant eccentric Kuiper belt objects
We have developed a method to rigorously estimate the longitude of perihelion bias for Kuiper belt observations. We find that the probability that the 10 known Kuiper belt objects with semimajor axis beyond 230 AU are drawn from a population with uniform longitude of perihelion is 1.2%. Combined with the observation that the orbital poles of these object are also clustered, the overall probability of detecting these two independent clusterings in a randomly distributed sample is 0.025%. While observational bias is clearly present in these observations, it is unlikely to explain the observed alignment of the distant eccentric Kuiper belt objects.
Quote from the intro "Planet 9 (hereafter P9), hypothesized to exist on a wide orbit around the Sun (Trujillo & Sheppard 2014, Batygin & Brown 2016a), is included in some of our simulations (see Section 3) to test its influence on the structure of the trans-Neptunian region and comet delivery. We find that P9 would enhance the flux of HTCs by ~30%. The inclination distribution of ECs (ecliptic comets) can be matched in a straightforward manner in a model without P9, but when P9 is included, it acts to increase the inclination dispersion of SDOs. This propagates into the inclination distribution of ECs, which then appears to be too broad to match observations" Agmartin (talk) 19:30, 26 June 2017 (UTC)
More from page 23 "The problems with P9 discussed above are related to the fact that the scattering disk at 50 < a < 200 au, which is the main source reservoir of ECs (Section 4.7), has significantly larger inclinations than in the model without P9. This happens because many SDOs interact with P9, with their orbital inclination being excited, and then return into the scattering disk with a < 200 au." Figure 5 on page 48 shows the distribution of a objects with Planet Nine but without the galactic tide and or stellar encounters, beyond the scattered disk with perihelia near 30 au this cloud represents objects dynamically controlled by Planet Nine. A sizable fraction of them have semimajor axes larger than Planet Nine. Agmartin (talk) 22:00, 26 June 2017 (UTC)
OSSOS VI. Striking Biases in the detection of large semimajor axis Trans-Neptunian Objects
New paper from the Outer Solar System Origins Survey, a quote from the abstract
We demonstrate the striking and non-intuitive biases that exist for the detection of TNOs with large semi-major axes. The eight large semi-major axis OSSOS detections are an independent dataset, of comparable size to the conglomerate samples used in previous studies. We conclude that the orbital distribution of the OSSOS sample is consistent with being detected from a uniform underlying angular distribution. Agmartin (talk) 15:54, 19 June 2017 (UTC)
Here are the objects from table 1. So the main difference is the main list has a>250au, BUT 3 new ones are >250! Tom Ruen (talk) 18:46, 19 June 2017 (UTC)
The OSSOS sample of TNOs with a > 150 au and q > 30 au
Plot (left) with location of the poles of the Extreme TNOs, similar to a this post on findplanetnine.com, with areas OSSOS had no or poor coverage marked. Agmartin (talk) 21:08, 19 June 2017 (UTC)
Some notes on individual objects in that plot, the two objects at 10 o'clock, one from OSSOS and one from Sheppard and Trujillo are both in the aligned group, the object at 7 o'clock has a semi-major axis of 1800 AU so it may also be influenced by the galactic tide. Agmartin (talk) 21:18, 19 June 2017 (UTC)
Added (above) 2 views of orbits, 4 OSSOS objects in orange with a>250au. With a side-view (not shown), I see none of the 4 orange objects have a similar inclination the proposed P9. Tom Ruen (talk) 13:40, 20 June 2017 (UTC)
Should we add the other 3 "new" objects (a>250au) to the article table, along with 2013 SY99? They've all now been added with MPEC designations and orbital parameters: [21]. Tom Ruen (talk) 13:49, 20 June 2017 (UTC)
Doing some nonpermissible OR, being curious about objects to include (beyond current 13), I expanded the B&B parameters with 250>a>200 and found 4 objects, and reduced by removing 35<q<30 AU, leaving 2 "new" objects 2000 CR105 and 2002 GB32, the first seems anti-aligned, and the second more an unhelpful case. 15 objects: q>35 AU, a>200 AU I considered this expansion since we want larger q to be far above Neptune, while a>250 seemed somewhat arbitrary, perhaps only defined because it isolated the original list of 6. But now that we have counter-cases anyway, seems better to include.
IIRC Mike Brown included 2000 CR105 with the other six somewhere, I don't recall if it was on his blog or one of the later papers. 2002 GB32 was plotted on Figure 1 of B&B as one of the dynamically unstable objects. Agmartin (talk) 15:40, 19 July 2017 (UTC)
Found it, the second paper Observational Constraints on the Orbit and Location of Planet Nine in the Outer Solar System mentions seven objects with a > 227 AU are aligned. It also mentions that 5 with a > 100 AU and q > 42 AU are also clustered 2000 CR105 is included in both groups. He also mentioned a lack of objects with 100 AU < a < 200 AU and q > 42 as part of the criteria used in that paper. However, since it was posted on arxiv Trujillo and Sheppard did find one of those objects 2014 SS349 and the OSSOS group added a second 2013 UT15. Agmartin (talk) 16:06, 19 July 2017 (UTC)
I plotted these objects as viewed from above the solar system, and viewed from the sun along the ecliptic centered away from milky way center. Viewed from the sun (near the earth), you can see most the objects are away from the milky way where its hard to see 23 magnitude objects among the bright star fields. I colored the anti-aligned objects red, and others blue, with hypothetical P9 green. I put boxes around the two objects with 250<a<200 AU that B&B would exclude.
Here's an interesting new source about the computer science behind the search. http://spectrum.ieee.org/aerospace/satellites/is-there-a-giant-planet-lurking-beyond-pluto In August a couple Berkeley grad students are going to run a new algorithm over archived photos to add them together and thus identify extremely faint objects moving along the predicted orbital path of P9. This computing will only take a few days, but may generate ~10,000 hits that will have to be investigated. JehochmanTalk15:35, 1 August 2017 (UTC)
Looks exciting! Also:
"Those odds are now steeper because the list of relevant oddball planetoids known to haunt the outer reaches of our solar system has lengthened: from 6 in early 2016 to 20, Trujillo says."
Six known in early 2016, seven were announced since then, they may have others awaiting better determination of their orbits. I recall one mentioned at a distance beyond 100 AU with no other details being released. Agmartin (talk) 18:59, 1 August 2017 (UTC)
Reading the article more carefully: thirteen from B&B's criteria, plus the 5 perpendicular, possibly rounded up. Agmartin (talk) 16:23, 2 August 2017 (UTC)
The mysterious and elusive ninth planet of our solar system that is believed to be in existence since 2014, has reportedly been located by a Mr C. Green of Hampshire, UK. Mr Green, an amateur astronomer, made the schoolbook-changing discovery using a Meade LightBridge 12"/304.8mm Reflector Telescope from his home observatory a month ago. ... If the discovery of Planet Nine, which has been dubbed as the most important astronomical discovery of a generation, is officially credited to Mr Green, he has vowed to name the planet after his cat, "Emoji"
I thought about using Planet Nine Found! as the title, but was worried it might be possible for people to throw things at me through the internet. Agmartin (talk) 19:33, 2 August 2017 (UTC)
"Although it is thought to be 8 to 10 times as massive as Earth and 2 to 4 times as wide, it seems to be maddeningly hard to spot." and later "So, if Planet Nine exists and is 10 times Earth’s mass, it must be within 25 degrees of the farthest point in its hypothetical orbit, he says. A smaller Planet Nine—Brown now favors a mass eight times that of Earth—would have 40 degrees of wiggle room to hide in."
Goddamn, I'm lazy. Still, probably notable enough to include in this article somehow, especially given it says Brown seems to find it more likely to be at 8 Earth masses (therefore making it harder to find) 134340Goat (talk) 00:56, 3 August 2017 (UTC)
There was a paper submitted by Batygin and Brown last October that I suspect the source of the diagram of the poles of distant object orbits in this post. I expect that is where we will see the details of why they prefer a lower mass, and also a smaller inclination as I saw in a video of one of their presentations. I recommend waiting for that paper. Agmartin (talk) 17:35, 3 August 2017 (UTC)
And this seems an interesting quote - “I actually think we will not discover Planet Nine by scanning the sky,” Brown says. “We could, but I think somebody will find it first in archival data,”…. Smkolins (talk) 09:54, 3 August 2017 (UTC)
Why is Planet Nine so large and yet so dim?
User:Headbomb has three times reverted my attempt to include a statement about how brightness for planets decreases with the fourth power of its distance, claiming "This claim is both 1) ill-defined and false 2) unsupported by references. This is WP:BRD stuff. You've been reverted, go to talk page and discuss."
Would anyone like to help me support this? I linked a calculation of planetary apparent magnitude, although you still have to look a bit to get the 1/16 brightness for double the distance. The relationship is approximate in the sense that the distance from the earth to planet is not identical to the sun to planet distance, although for distances of hundreds of AUs this is effectively true. I also noted that doubling the distance is about 3 magnitudes dimmer, although the exact brightness ratio for 3 magitudes is 100^(3/5)≈15.849. Tom Ruen (talk) 05:47, 5 August 2017 (UTC)
A planet moved twice as far from the sun will be 1/16th as bright, or about 3 magnitudes dimmer.
"The relationship is approximate in the sense that the distance from the earth to planet is not identical to the sun to planet distance". Exactly. Unqualified, the reader will think if you double Mars' distance, you'll cut its brightness to 1/16th, and that's just not true. Even worse when you think about Mercury or Venus.
The exact fraction you get by double the distance is not important, every one understand that things get dimmer as you move them away. Explaining the simplification made to get such a fraction will distract the reader with needlessly dense passages. The important point is made: Due to its extreme distance, we expect it to be at least 600 times dimmer than Pluto.
Also due to the extreme eccentricity, Planet Nine's brightness would vary quite a bit at perihelion (200 AU), than at aphelion (1200 AU), and by a lot more than a factor of 16. Headbomb {t · c · p · b}05:59, 5 August 2017 (UTC)
So the statement can be qualified or clarified however you think is helpful, which can include a note reference to not clutter the paragraph. Reverting rather than improving is unhelpful. And the statement is true for P9's predicted elliptical orbit, so when it is near aphelion 1000AU vs 500AU it will be about 3 magnitudes dimmer. And as you say from 200 to 1200 AU, it could be 6^4=1296 x dimmer from perihelion to aphelion, or 7.8 magnitudes. Comparing to similarly sized Neptune would be more useful since Neptune is about the same distance as Pluto, and expected to be a similar size. Comparing to Pluto just adds to the mystery, why tiny Pluto much smaller and 600 times brighter. Tom Ruen (talk) 06:10, 5 August 2017 (UTC)
You may want to qualify the statement by pointing out that in the outer solar system the distance from the Sun to the object and the distance from the object to the Earth are similar enough that the more complex equation can be approximated by distance^4. Perhaps
"In the distant reaches of the outer Solar System a planet moved twice as far from the Sun will appear approximately 1/16th as bright, or about 3 magnitudes dimmer, as viewed from Earth."
I'd much rather have a short note that the apparent luminosity (or whatever the technical term is for this) of post-Kuiper belt objects / TNOs / whatever as seen from earth varies as 1/d4 (assuming it is reflection-dominated), which can then be vulgarized as double distance = 16 less bright. Backed with references. But this is out of place in the main text. Headbomb {t · c · p · b}17:10, 5 August 2017 (UTC)
That this planet has not been discovered yet should not strike anyone by surprise. Since the brightness of a body decreases by the fourth power of its distance from the sun, even an object as large as Neptune would be a million times dimmer than that.Wnmyers (talk) 07:52, 8 August 2017 (UTC)
High Inclination objects
A bit of OR (slaps wrist with ruler)
According to a search of JPL's small bodies database there are 16 asteroids with semimajor axis > 150 AU and inclination > 40 degrees. I have plotted the argument of perihelion relative to Planet Nine vs inclination and longitude of ascending node relative to Planet Nine vs inclination with figure 9 from Batygin and Brown 2016 as the backgrounds link1, link2. It appears to me that asteroids with semimajor axis greater than 300 AU follow the tracks from B&B about as well as the five on their plot even if when the perihelion is inside Jupiter's orbit, two have 3 < q < 5 AU ( 2005 VX3[24] and 2017 MB7[25]) and two q < 3 (2002 RN109[26] and 2007 DA61[27]). Unfortunately all were only observe for short arcs. I note the tracks from B&B are for objects with a > 500 AU and that when Sailinfest etal 2017 (mentioned in second paragraph of the Secular dynamics of extreme TNOs section) discussed perpendicular objects those with a > 300 AU crossed the orbits of the other planets. Agmartin (talk) 21:56, 8 August 2017 (UTC)
link1 and link 2 are changed to correct mistake made a mistake converting 0 - 360 range to -180 - 180 range, 2007 DA61 no longer fits tracks from B&B 2016. Agmartin (talk) 01:01, 10 August 2017 (UTC)
Identifying range of semimajor axes and eccentricities that allow orbits of know ETNO's to remain stable even if their semimajor axes vary. Agmartin (talk) 18:54, 22 June 2017 (UTC)
"it has been proposed that resonant interaction between Planet Nine and distant, confined objects may inform the present-day semimajor axis and location of Planet Nine along its orbit, if the resonances at play can be identified. Inspired by this notion, we have carried out a suite of numerical simulations aimed at characterizing capture probabilities of Planet Nine mean-motion resonances, and have found that numerous high-order resonances successfully trap Kuiper belt objects, precluding a simple identification of the dominant commensurability. At the same time, our simulations show that resonant relationships are indeed key to maintaining long-term stability of confined KBOs, and breaking the resonant lock results in the rapid onset of dynamical instabilities within the distant Kuiper Belt."
While this runs counter to a number of papers discussed in the article, I'm waiting for it to show up on arXiv or in the press before adding it. Agmartin (talk) 17:16, 5 August 2017 (UTC)
It would be good when the above paper arrives to combine all talk of resonances in one section. It seems Batygin and Brown first brought the idea up, then Maholtra, Volk and Wang fleshed out their take on it, then Milholland and Laughlin, etc. There are two problems that I see with making a single section (or subsection) on resonances. The first is that the Maholtra material (and excellent table) is in the 'Alternate hyphotheses' section (and other stuff is in 'Subsequent efforts toward indirect detection'/'Optimal orbit if objects are in strong resonances'). The Maholtra/Volk/Wang info on resonances should move. The second problem is that Milholland and Laughlin's paper is oversimplified, as they specify a few possible resonant configurations for certain bodies. Assscroft (talk) 00:52, 8 August 2017 (UTC)
I was thinking of a mean-motion resonances vs secular dynamics section describing the two proposed mechanisms once that paper came out. Right now the indirect detection section is by paper because it I found it easier to add individual summaries as I read the papers. For the Milholland and Laughlin paper I stuck to the specific configuration because the graphic of that one is what showed up in the press. Agmartin (talk) 16:56, 8 August 2017 (UTC)
At 9;34 she shows a plot of the chances of individual object being in N/1 and N/2 resonances, 1/4 - 1/2; and for six objects randomly chosen objects all being in N/1 and N/2 resonances, a few percent at most. Agmartin (talk) 16:42, 8 August 2017 (UTC)
part of another abstract, this from the upcoming DPS conference
"In this talk, we will characterize the dynamical processes at play, from semi-analytic grounds. Specifically, we will show that although the long-term survival of the clustered population of long-period KBOs is enabled by a web of mean-motion resonances driven by Planet Nine, it is the secular dynamics embedded within these resonances that regulates the orbital confinement and perihelion detachment of distant Kuiper belt objects. Moreover, we will demonstrate that the onset of large-amplitude oscillations of orbital inclinations is accomplished through capture of low-inclination objects into a high-order secular resonance and identify the specific harmonic that drives the evolution." Agmartin (talk) 21:34, 12 August 2017 (UTC)
"We find that only 1 - 6 per cent of FFLOPs are ensnared by stars, even with the most optimal initial conditions for capture in star-forming regions (one FFLOP per star, and highly correlated stellar velocities to facilitate capture). Depending on the initial conditions of the star-forming regions, only 5 - 10 of 10000 planets are captured onto orbits that lie within the constraints for Planet 9. When we apply an additional environmental constraint for Solar system formation - namely the injection of short-lived radioisotopes into the Sun's protoplanetary disc from supernovae - we find that the probability for the capture of Planet 9 to be almost zero." Agmartin (talk) 16:33, 5 September 2017 (UTC)
I was probably too harsh on New Scientist, they only mentioned capturing from another star, but didn't clearly point out that the free-floating planet capture is a third idea. Agmartin (talk) 19:38, 11 September 2017 (UTC)
We now know of about 10 of these anti-aligned objects, so can look at their longitudes of perihelion and get a direct estimate of the longitude of perihelion of Planet Nine (if you care about the details: we actually exclude the two most recently detected objects as they came from the OSSOS survey which has been shown to have striking biases in the objects that it finds). When we do this, we find a value of 235 with an uncertainty of 12 degrees.
And the good news is that can now estimate the node much more precisely. If we take those same eccentric distant Kuiper belt objects and look at their nodes, we find that Planet Nine has a longitude of ascending node of ~94 degrees. Agmartin (talk) 21:36, 21 September 2017 (UTC)
I think the article could make more clear the differences between Centaurs and TNOs. Are the minor planets mentioned in section Batygin and Brown (2016) - Clustering, Centaurs? Also for detection, since meteor impacts are traced back to their origin based on impact speed (at least for the Chelyabinsk meteor#Origin), are there any studies to use meteor origins to get a better clue of Planet 9s orbit (If origin could be traced to related regions)? prokaryotes (talk) 13:46, 14 October 2017 (UTC)
Oops
I was experimenting with a different arrangement of the article, in what I thought was my sandbox, but had wrong tab open. Sorry about the mess I made of it. Back to normal now, closing this tab. Agmartin (talk) 19:41, 13 October 2017 (UTC)
@Agmartin: For the next time, you can undo back to a particular version in one edit by
selecting the Cur beside it in in View history;
choosing undo from the resulting diff view.
(For step 1, if there are other later edits you don't want to affect, you can also diff any two particular versions, although that increases the chance of an edit conflict in step 2.) --Ørjan (talk) 04:36, 14 October 2017 (UTC)
Here's something: In search of the ninth planet Oct 17, 2017 Astronomers also have another newly discovered TNO to include in their indirect methods of detecting Planet Nine. The Dark Energy Survey collaboration, a large group of scientists including several U-M scientists, has discovered another TNO that has a high orbital inclination compared to the plane of the solar system: it is tilted about 54 degrees relative to the solar system's plane. ... In an analysis of this new object, Becker and her team have found that this object experiences resonance hopping as well in the presence of Planet Nine, showing that this phenomenon extends to even more unusual orbits.
Revised version of article
I have a rearranged and partially rewritten version of Planet Nine in my sandbox. You can view that, right? First, I have moved the summary back above the table of contents. Second, to address one of the reasons for the "too technical" notice, instead of being a list of result by a series of papers, I organized the first part with the answers to the questions Who, Where, What, Why, When, and How in mind. For the dynamics section I used the five pieces of evidence cited by Batygin and Brown in a recent NASA article as an initial outline. After describing the clustering that provoked the recent speculation about Planet Nine I describe what happens in simulations then describe the dynamics that produces these results, before moving on to the other effects. I decided to place the alternate hypotheses after origins because the low probabilities of the mechanisms proposed served as a good lead in. Those are ordered by most skeptical, i.e. no clustering in models or in observations, then from the least similar model with no planet, to a planet with objects in strong resonances, to the Trujillo and Sheppard that began recent work, and finally ending with some earlier models. Next is searches with telescopes, which I think most reader will find more interesting than the more technical indirect detection methods. I'm thinking of moving some pieces of the material in the latter section, for example that on dynamical stability of distant objects, up into the dynamics or simulation sections. And some of the optimal orbit if in strong resonances up to the Object in lower eccentricity orbit section. That depends if it can be done without making then cluttered or confusing.
If I removed it wasn't intentional, that may be a change that was made between when I copied the article to my sandbox to begin editing and that I missed before I posted the revised version. Agmartin (talk) 21:36, 19 October 2017 (UTC)
As prokaryotes may be hinting, doing such a large rearrangement in a single edit makes Wikipedia's diff views (especially the default one, but also the improved wikEdDiff) nearly useless. I had to give up proofreading after the "Numerical simulations of extreme TNOs" section because wikEdDiff started locking up after that. --Ørjan (talk) 08:40, 20 October 2017 (UTC)
The article as previous written read more as a history discussing various papers instead of an article about Planet Nine. That made sense when it was a few papers but the way it has grown around that outline that the article had gotten unwieldy. I didn't see any way to make more readable to a general audience without first pulling it apart and reorganizing it. After reorganizing it parts obviously would need rewriting before it could be followed. Not being an efficient typist or an enthusiastic writer I didn't believe it would have been practical to revise the article piece by piece while others were also making changes so I used my sandbox instead. Agmartin (talk) 19:31, 20 October 2017 (UTC)
What I changed
material in general is back above TOC
Trujillo and Sheppard and de la Fuente Marcos moved down to alternate hypotheses, IIRC they are unchanged.
the original three alternate hypotheses are reordered but otherwise unchanged
what was the intro to the Hypothesis section is now in Previous models with additional planets
moved the George Forbes material there, and the pieces that discussed Sedna and 2012 VP113 are merged into one paragraph
changed title of Hypothesis section to Dynamical effects
its intro is modeled on numerous recent articles listing five reasons Batygin and Brown think Plant Nine exists
Orbital clustering and high perihelion objects is the previous Clustering section with brief discussion of T&S 2014 and a bit about Sedna and 2012 VP113 added
Simulation section renamed, largely rewritten, it describes what happens only, why is moved to next section
parts of what discussed perpendicular objects is moved to that section
most of what was in Planet Nine cloud is now in the final paragraph of this section
Secular and resonant dynamics of extreme TNOs is new section, I'm thinking about adding images
Objects with perpendicular orbits is mostly rewritten
It mainly describes the dynamics
Rereading it there a couple of things I left out that I will add back in
High inclination TNOs and Solar obliquity are largely unchanged
Oort cloud and Comets merged
Most of material that was in Oort cloud that instead discussed the P9 cloud is removed
Origin is moved up but unchanged
From Searches for Planet Nine on down sections are relocated and renamed but almost all are unchanged
Batygin and Morbidelli paragragh of Secular dynamics of extreme TNOs removed as redundant since it formed basis of Secular and resonant dynamics of extreme TNOs section earlier in article
"Simulations have shown that objects with a semi-major axis less than 150 AU are largely unaffected by the presence of Planet Nine, because they have a very low chance of coming in its vicinity." is shortened to "and little effect inside 150 AU" in Numerical simulations of extreme TNOs; "The simulation also predicts a yet-to-be-discovered population of high perihelion objects that have semi-major axes greater than 250 AU, and orbits that would be aligned with Planet Nine. Although they may include high eccentricity objects the most stable of these objects would have lower eccentricities." is covered in Secular and resonant dynamics of extreme TNOs "The orbits of objects that are unstable, for example some that are initially aligned with Planet Nine, precess until parts of the orbits are tangent to that of Planet Nine, leading to close encounters. Some stable orbits do exist for aligned objects with larger eccentricities. Objects in these orbits have yet to be observed, however, and an additional perturbation would have been required to be captured in these orbits."
Sorry, I didn't mean to critize the deletion per se, I just wondered, since the edit description was just "typo", and searching for parts of its text in the final version found nothing, whether it had disappeared due to an editing mistake. --Ørjan (talk) 04:56, 22 October 2017 (UTC)
Most of what was in the general section was above the table of contents when I copied it to my sandbox to rearrange. Other than the mention of George Forbes and the inclination diagram it is largely unchanged, though I did rewrite part of he first sentence of the second paragragh. I think the intro should stick to Planet Nine only so I moved the mention of George Forbes to 'previous models with additional planets' and I left out the inclination diagram because I think that is a simpler concept than what the person who added the 'too technical' box meant. I think the brief summary (I see it as the TL;DR version) above the table of contents is more useful to those who just want the basics and don't want to wade into an article as long as this has gotten. Agmartin (talk) 17:27, 20 October 2017 (UTC)
Image to add
I've uploaded this image to the Commons:
Secular evolution of eTNOs induced by Planet Nine
The curves are modeled on upper right part of Fig. 2 of Dynamical Evolution Induced by Planet Nine by Konstantin Batygin and Alessandro Morbidelli. https://arxiv.org/abs/1710.01804
After finishing this plot I overlayed the curves from B&M 2017 and determined that while they are similar they clearly do not match those in the diagram from B&M 2017.
I was wondering would wikipedia consider this not to be entirely my work and delete the file?
Should I claim it is Fair Use instead? Agmartin (talk) 20:11, 23 October 2017 (UTC)
'In recent simulations of planetesimal formation via the streaming instability performed by Carrera etal 2017, a massive (60 - 130 MEarth) planetesimal belt forms beyond 100 au. This ultracold belt of planetesimals, which we will dub a cryobelt forms early due to effcient photoevaporation in the outer regions of the disc.'
'Out of all simulations with an inner edge of the cryobelt at 100 au, approximately 30% (11/35) were successful. For simulations with an inner edge of the cryobelt at 200 au the success rate was 20% (7/35).'
The simulations start with Planet Nine's perihelion at 30 AU, and interacting with Neptune, which might affect their success rate. The planetesimals form quickly so the model would work if Planet Nine is scattered out early, as they assume, and I guess it would also work late like in the Nice model. Now I'm wondering if the inclination instability Madigan proposed could still occur with Planet Nine in the midst of the disk. Agmartin (talk) 18:52, 24 October 2017 (UTC)
on "Temporary or coincidental nature of clustering"
I think it would be relevant to talk why in physics a new discovery requires a 5 sigma in order to be taken seriously. Meanwhile, some recent hyped "discoveries" with 3 sigma proved to be just noise. Such a ?debate?/analogy could be relevant to mention in this section, to show that things like this are not unique to this specific case. 86.123.22.216 (talk) 10:27, 29 October 2017 (UTC)
IIRC the initial 0.007% odds of the clustering of the original 6 was 3.7 sigma. I think the new discoveries including aligned objects and the one at ~90 degrees may have made the odds less steep and the sigma smaller. But I have read that the clustering of the original six was tighter than than they saw in simulations (see Fig 2 in https://arxiv.org/abs/1603.05712 where the success rate never leaves single digit percentages) so the clustering in the data may never reach 5 sigma. Agmartin (talk) 19:07, 29 October 2017 (UTC)
And one thing about the Shankman et al paper discussed in that section. I suspect the reason their results differ from Batygin and Brown's is that they are using real objects with one possible orbit of Planet Nine. They may be starting with the objects in unstable orbits because they are not in resonances with Planet Nine or are not phase protected using these initial conditions. Agmartin (talk) 19:47, 29 October 2017 (UTC)
I suppose a big difference between quantum physics and planetary astronomy is that you can actually see your targets in astronomy, while everything from a particle accelerator is statistical inference, although exoplanetology is largely back into the black box again. Tom Ruen (talk) 19:56, 29 October 2017 (UTC)
From one of the abstracts (click on online program, Tuesday, 216 and Thursday, 405 for others) of next weeks DPS meeting. I wonder when they will release the data.
Detection Bias for Trans-Neptunian Objects on Highly Elliptical Orbits with the Dark Energy Survey
"We report the discovery of several new "extreme" trans-Neptunian objects (ETNOs) with semimajor axis > 150 AU discovered using the Dark Energy Survey (DES). This currently ongoing survey is entering its fifth planned year of operation on the 4m Blanco telescope in Chile and is imaging 5000 deg2 in the grizY passbands to a limiting magnitude of r~23.8. " Agmartin (talk) 21:39, 10 October 2017 (UTC)
Another one mentioned here
Evaluating the Dynamical Stability of Outer Solar System Objects in the Presence of Planet Nine
"We also announce the discovery of a new large semi-major axis, highly-inclined TNO, found in the Dark Energy Survey (DES) data. This new object’s orbit places it in the same population as was used to predict the existence of Planet Nine, and so this new object also helps constrain the orbital elements of the proposed Planet Nine." Agmartin (talk) 21:43, 10 October 2017 (UTC)
They often don't submit the data to MPC until after the paper discussing it is accepted. I see their other new one pe82, with a ~320 AU and anti-aligned like most of the others, in the ppt. Agmartin (talk) 20:51, 24 October 2017 (UTC)
Thanks! I see 'Caju' on slide 9, with its orbit drawn, and it says it fits the P9 set. Also reading plots argperi≈350°, long-asc-node≈133°, so that's enough to construct an orbit, just not a current position. I imagine they're looking for precovery images to improve the orbital parameters? Tom Ruen (talk) 02:21, 25 October 2017 (UTC)
is that it doesn't tell a story. It's just a list of different hypotheses. No wonder people are finding it hard to read. Orbital mechanics is complicated and people need to be drawn in. I would suggest going with a more historical approach, and focus more on the people involved. Serendipodous21:49, 25 October 2017 (UTC)
I thought the historical approach that the article had before I rearranged it was what it made it look like a list of different hypotheses. That's why I moved the Trujillo and Sheppard, de la Fuente Marcos, and other history down; and so the first part of the article would be focused on Planet Nine. Agmartin (talk) 16:53, 26 October 2017 (UTC)
The problem is how the article progressed. Each new nugget of information was added as it became known. If and when Planet Nine is discovered, it needs to be entirely reworked. Leitmotiv (talk) 20:11, 26 October 2017 (UTC)
Personally, if that matters at all, I find this article fantastic, and for the most part well-ordered (and fascinating). It's a credit to Wikipedia. No idea if I'm in the minority in this opinion. Occasionally the 'research paper updates' need to be reorganised by theme, but that will never be apparent as they come in. Assscroft (talk) 01:06, 31 October 2017 (UTC)
You're definitely in the minority here, because Wikipedia isn't editing for Wikipedians. It's editing for the general public or layman. Sure this article is great for astronomers, but for the general reader this goes down as easily as a pint of caster oil. User:Leitmotiv
Those who are "improving" this article with endless techno-bable and math, this is one more reminder: Wikipedia is not a manual, guidebook, textbook, or scientific journal, Wikipedia:Make technical articles understandable. Quoting: "Every reasonable attempt should be made to ensure that material is presented in the most widely understandable manner possible. If an article is written in a highly technical manner, but the material permits a more understandable explanation, then editors are strongly encouraged to rewrite it.
Quote from WP:What Wikipedia is not: #7 "Scientific journals and research papers. A Wikipedia article should not be presented on the assumption that the reader is well-versed in the topic's field. Introductory language in the lead (and also maybe the initial sections) of the article should be written in plain terms and concepts that can be understood by any literate reader of Wikipedia without any knowledge in the given field before advancing to more detailed explanations of the topic."
A request was placed as a header in the article and it has been consistently ignored. As stated above in this section, a reasonable request is to add a very accessible/readable/understandable summary to every key section, followed by the physics involved. A second alternative is WP:Blow it up and start over, which looks very tempting right now. Thank you, BatteryIncluded (talk) 16:32, 15 November 2017 (UTC)
Sorry, I thought I was addressing that (yes, I did read it before making the additions) by explaining some terms that were used but have no articles on wikipedia to link, for example phase protection, which previously was just thrown out there with no explanation, and how Planet Nine produces what is observed in simulations. The math is in notes, which I was under the impression that few people actually read, but I included in case someone wanted to confirm details without searching for them in the papers. The last physics course I took was one semester as a college freshman back in the 1980s, I've tried to explain as much as I could at that level, I thought these days they covered things like angular momentum, torque, and precession in high school. I've included diagrams that I've referred to in the explanations, and tried to paint a picture in the readers' minds where there wasn't room for one. What may look like fussy details in the last paragraphs of the secular dynamics and resonant dynamics sections was material that previously was scattered through several paragraphs before that I thought would appear more relevant there than in isolation. Perhaps I should rename Dynamical effects, Evidence of Planet Nine, and move the dynamics to the end if it is scaring people.Agmartin (talk) 22:11, 15 November 2017 (UTC)
You are doing a very good job at softening the technical terms into a more comprehensible language. There will always be some technical language required to explain the geometry and orbits, but I find that all or most of the key terms are explained early in the article. Thanks. It is a monumental task. BatteryIncluded (talk) 15:30, 19 November 2017 (UTC)
Chaotic Dynamics of Trans-Neptunian Objects Perturbed by Planet Nine
arxiv.org Sam Hadden, Gongjie Li, Matthew J. Payne, Matthew J. Holman
Observations of clustering among the orbits of the most distant trans-Neptunian objects (TNOs) has inspired interest in the possibility of an undiscovered ninth planet lurking in the outskirts of the solar system. Numerical simulations by a number of authors have demonstrated that, with appropriate choices of planet mass and orbit, such a planet can maintain clustering in the orbital elements of the population of distant TNOs, similar to the observed sample. However, many aspects of the rich underlying dynamical processes induced by such a distant eccentric perturber have not been fully explored. We report the results of our investigation of the dynamics of coplanar test-particles which interact with a massive body on an circular orbit (Neptune) and a massive body on a more distant, highly eccentric orbit (the putative Planet Nine). We find that a detailed examination of our idealized simulations affords tremendous insight into the rich test-particle dynamics that are possible. In particular, we find that chaos and resonance overlap plays an important role in particles' dynamical evolution. We develop a simple mapping model that allows us to understand in detail the web of overlapped mean-motion resonances explored by chaotically evolving particles. We also demonstrate that gravitational interactions with Neptune can have profound effect on the orbital evolution of particles. Our results serve as a starting point for a better understanding of the dynamical behavior observed in more complicated simulations that can be used to constrain the mass and orbit of Planet Nine.
Daniel Fischer @cosmos4u
Eek, have radio astronomers killed the #planetnine postulated by @kbatygin and @plutokiller?! Just learned of an upcoming paper based... 1/3
1:11 PM - 25 Oct 2017 from Cologne, Germany
Daniel Fischer @cosmos4u Oct 25
... on precision pulsar timing which nails down the barycenter of the solar system with enormous precision. The known planets show ... 2/3
Daniel Fischer @cosmos4u Oct 25
... clearly visible timing effects - but there are none from #planetnine where there should be. Paper out in a few months - stay tuned. 3/3
Mike Brown @plutokiller Oct 25
Replying to @cosmos4u @kbatygin
can't wait to read! difficulty, I think, is that P9 is essentially not moving and that pulsars aren't sensitive to a stationary tide. Maybe.
Konstantin Batygin @kbatygin Oct 25
I agree w @plutokiller, but there might be at least an interesting constraint in there
Jonathan Hochman @Jehochman Oct 26
This https://arxiv.org/abs/1008.3607 says no results for Uranus or Neptune. If not sensitive to those two, how to measure P9?
Mike Brown @plutokiller Oct 26
well, that WAS 7 years ago. there should be a ton of new high quality data.
Jonathan Hochman @Jehochman Oct 26
It would be funny if they said impossible and then you pull out a picture...
Mike Brown @plutokiller Oct 26
yes! also, we're willing to be proven wrong. if they can do it that is support important.
And yet there are so many indicators for another big planet in our solar system (Solar obliquity, missing big planet compared to other star systems...) Why are there no recent spacecraft missions to map our solar system in more detail? prokaryotes (talk) 18:55, 30 October 2017 (UTC)
The data from Gaia will take years to process, and it has enough accuracy that it should be able to do what you're asking. It just requires researchers to look for the right stuff. Primefac (talk) 19:01, 30 October 2017 (UTC)
I see it says there "When Gaia entered regular scientific operations in July 2014, it was configured to routinely process stars in the magnitude range 3 – 20" so maybe objects dimmer than 20 will be ignored, including P9? Tom Ruen (talk) 02:32, 31 October 2017 (UTC)
Thinking about this, for the effects of Planet Nine to be detectable they would need to see a change in velocity that did not fit a model of the solar system without Planet Nine. For example changes in the velocity of the barycenter due to Planet Nine's velocity changing with time as it moves in its orbit, steady motion due to Planet Nine wouldn't be distinguishable from the Sun's motion among the stars. Or they would need to detect unexpected motions of the other planets like that found in the Cassini data, if that actually exists. Agmartin (talk) 17:05, 31 October 2017 (UTC)
My impression is we'd have lots of evidence of P9 if we had centuries of data, but the effects are too small in the short term. I imagine flinging out 10,000 microprobes in all directions with telemetry data as they go beyond pluto could tell us alot, effects like the Pioneer anomaly, but it would still take a couple decades, and surely telescopes will find a large planet faster. Tom Ruen (talk) 06:45, 1 November 2017 (UTC)
P9 would change where the barycentre is. If you calculate the barycentre from the known major masses and assume the minor stuff (like the Oort cloud and small asteroids, in terms of the effect on the barycentre) are evenly distributed, then you could predict the path of, e.g., Mars. If Mars then follows a different path from the prediction, then then predicted barycentre is off, and you could (in theory) get the actual barycentre from the orbit. The difference points you to the missing mass (or balance thereof, if there are multiple missing major masses). So you don't really need the long timeline to wait for P9 to move to see its effect on the barycentre. If you have precise enough measurements, and lots of computing power. I think that's what they were trying to do with the Cassini measurements at Saturn. Tbayboy (talk) 14:32, 1 November 2017 (UTC)
I don't see barycenter as a primary factor. How do you even compute that except by the mass-position sum of all know bodies?! Perturbation doesn't need any assumptions about centers, rather it looks at cyclic longitudinal shifts, which requires long periods of data collection. It is surprising anomalies of Cassini could be caused by P9 out at 1000AU, although really I think it would be more the entire Saturn system shifting minutely from expected positions. So this seems more of a tidal force (decreasing with the third power of distance), with P9's gravity is slightly stronger at Saturn than earth IF P9 happens to be on the same side of the sun. Tom Ruen (talk) 22:42, 1 November 2017 (UTC)
I would also think that the effects on TNO's lessens over time, making detection and attribution harder. Bottom line, unless that study is accessible we are left with speculations. prokaryotes (talk) 19:06, 1 November 2017 (UTC)
As of yesterday(!) we now have statistically rigorous calculations of best fit orbit and mass of P9 and, critically, uncertainties on all of these parameters. Along with that comes a rigorous calculation of a probability that that is no P9: 0.01%
(papers with all of the details coming soon[ish] to an arXiv near you)
As in Talk:Planet_Nine#No_Planet_Nine?, words like "soon[ish]" and "stay tuned" should be taken with a grain of salt when it comes to publication dates. I'd not be surprised if the Pulsar timing paper takes another 6 months (the author has to finish other work first). It's similar for this one. But I have asked Mike Brown on Twitter, if it doesn't get burried and I get a response I'll tell you.--Renerpho (talk) 06:54, 13 March 2018 (UTC)
Today Planet Nine was one of the topics. Some relevant tweets
Michele Bannister @astrokiwi
.@StephHamy820 using @theDESurvey difference imaging for TNO discovery. Most of 200 objects at i>10 deg. Three objects with q > 35, a > 250 au thus far #TNO2018. working on characterizing observational bias for @theDESurvey analysis. Three extreme TNOs found at greatest point of sensitivity #TNO2018. one detection in DES is a bright r ~ 21.5 (H=4.3) extreme TNO, a = 450 au, i = 54.1 deg, q = 35 au #TNO2018. simulations of this TNO with J. Becker show dramatically different behaviour with/without an extra distant planet #TNO2018[30]
Holman: testing Planet 9 idea with ranging data from New Horizons spacecraft and from very old observations of Pluto scanned. Finds a patch of sky where fits are improved if you add a giant planet tugging on Cassini (not NH, oops) or Pluto. #TNO2018. Holman: the residuals he used for fitting in his paper are actually wrong! #TNO2018. showing dynamically how P9 could align TNOs (has to do with resonance stability, from Hadden et al. paper). Says there will be temporary resonant sticking, NOT long term res. stability #TNO2018[31]
Mike Alexandersen @Mikea1985
Holman looking for a planet in the residuals of Plutos motion (over 100 years of data) other bright TNOs (up to decades of data) and Cassini spacecraft data (meter-scale accuracy over several years). #TNO2018. Holman different groups find different residuals, so it's unclear that this actually provides constraints. One set of residuals (which he claims might be overfitted), hardly allows any additional planet anywhere. #TNO2018. Holman can consistently rule out most of the sky, but cannot consistently find a "best fit"/"most likely" area. #TNO2018[32]
Michele Bannister @astrokiwi
Holman exploring a completely different approach for modelling mass in outer Solar System, using improved orbit of hundred-year arc on longest-known TNO, Pluto, (needed for trajectory of @NewHorizons2015) #TNO2018. using an old idea (Hogg et al. 1990s). orbits are tidally distorted by a distant planet. Can it be constrained by residuals from fitting orbits of Pluto & 500+ other TNOs? #TNO2018[33]
Dr. Sam @sundogplanets
Trujillo has a prediction for where planet 9 should be on the sky based on stability simulations of "extreme" TNOs and different planet 9 orbits #TNO2018[34]
Dr. Sam @sundogplanets
Sheppard: VP & Sedna are in very different part of a-q space than anything else in solar system. Lower q may have gotten there thru resonances, but not these 2. #TNO2018. Oo! New high-q TNO, discovered at 83 AU #TNO2018. shows with a certain planet 9 orbit, it will stay confined in long. peri #TNO2018. Found another big TNO (possibly top 10) and it has a moon and ALMA data, so they'll know for sure soon how big it is #TNO2018[35]
Stephanie Hamilton @StephHamy820
Sheppard: New ETNO with perihelion of 65au, aphelion of 2000au. Nice! #TNO2018[36]
Michele Bannister @astrokiwi
Sheppard: large distant TNO survey; use Subaru & Blanco for discovery, Magellan & DCT for recovery. Reduced down to two images for discovery rather than three, allowing more sky to be covered #TNO2018. trying to cover more sky to make a survey that is more uniform in longitude of perihelion. 97 discoveries at d > 50 au (only track these ones). New TNO with 3-year arc, q = 65 au, d=83 au, Q ~ 2000 au, long-term stable orbit #TNO2018. Sheppard new TNO has a ~ 1100 au, reasonably large uncertainties still. #TNO2018[37]
The new high-q TNO is probably the object we know as V774104. There has been some confusion about this object, see here and here. Some mistakes happened during in the announcement, so the object's internal designation is different.[38] I'd be cautious to include this information in any Wikipedia article, because 1. there is no official confirmation yet, and 2. Brown et al. haven't been able to include it in their calculations (they also don't have the details).[39] --Renerpho (talk) 20:00, 29 March 2018 (UTC)
I agree about not adding it to the article yet, I thought it was too early to add details from the pptx file about 'caju' to the table, but seeing that has it mentioned in several articles and that its orbit was included in an article at the planetary society I didn't object when it was. Agmartin (talk) 20:32, 29 March 2018 (UTC)
Mike Alexandersen @Mikea1985
Kavelaars (@jjkavelaars): We argue against others not because we dislike them, but because we're scientists. It's our job to question and scrutinize theories and claimed results. #TNO2018. unfortunately it's very difficult to get modelers to give you their simulation outputs so that you can test the models (for example with the @OSSOSurvey survey simulator). #TNO2018. "Again, I'm going to show the same figure as Chad and say the opposite." With time the alignment in 150-250 au has gone away, and the claimed alignment has shifted to 250+ ah. Kavelaars predicts with time that alignment will disappear too. #TNO2018. the biases for small semi-major axis is completely different from that for large semi-major axis. You can't use a lack of bias in one to assume a lack of bias in the other. "You're putting apples and peanuts together." #TNO2018. come to Victoria in May 2019 for a "New Horizons in Planetary Science" meeting sponsored by @almaobs . #TNO2018[40]Agmartin (talk) 19:28, 29 March 2018 (UTC)
AAS Division Dynamical Astronomy conference is this week. This abstract is relevant to Planet Nine
The prevalence of resonances among large-a transneptunian objects
By carefully analyzing the astrometric data of all known large semimajor axis objects, we show that a very large fraction of the objects are in fact likely in high-order mean-motion resonances with Neptune. This prevealence for actually being resonant with Neptune would imply that hypothesized planets are problematic as they would remove the detached objects from these resonances. Instead, we favor a view in which the large-a population is the surviving remnant of a massive early scattering disk, whose surviving members are sculpted mostly by diffusive gravitational interactions with the four giant planets over the last four gigayears, but whose initial emplacement mechanism (in particular: perihelion lifting mechanism) is still unclear but of critical importance to the early Solar System's evolution.
Shepherding in a Self-Gravitating Disk of Trans-Neptunian Objects
New paper appears to be claiming that a massive disk with modest and varying eccentricity can produce a cluster of objects anti-aligned to it by preventing their precession. I think that's what they are claiming at least. Agmartin (talk) 17:20, 20 April 2018 (UTC)
Looking at it more closely, the points with no precession are the neutral position at the centers of the curves which they plot in a different manner than Batygin and Brown did. In this article their disk is co-planar with the planets. Agmartin (talk) 21:23, 20 April 2018 (UTC)
I can't figure out how does P9 and the streak on IBEX map align. Can someone help? If P9 is real and has a meaningful magnetic field, then the termination shock seen in IBEX should show signs. Nergaal (talk) 09:00, 29 April 2018 (UTC)
If Planet Nine's path in the article is correct it would be roughly opposite the heliospheric nose, I suppose that would be called the tail. There might be some natural noise in that direction that would interfere with detecting it the way you hope. Agmartin (talk) 18:33, 30 April 2018 (UTC)
barycentric vs heliocentric
Where were the numbers for the barycentric orbits found? Are they from the minor planet center, JPL's small body database, or somewhere else? Agmartin (talk) 20:45, 7 May 2018 (UTC)
The Generation of the Distant Kuiper Belt by Planet Nine from an Initially Broad Perihelion Distribution
New paper by Tali Khain, Konstantin Batygin, and Michael E. Brown examines whether which object remain stable after Planet Nine is captured on its proposed orbit starting with either a narrow perihelion distribution (similar to scattered disk objects) or a broad distribution due to their perihelia also being raised by nearby stars. Agmartin (talk) 18:46, 1 May 2018 (UTC)
I tested a SVG orbital chart, including the 13 known TNOs with hypothetical Planet Nine. I added a background grid for scale, with 100 AU fine units, and 1000 AU coarse units. I also rotated for Ecliptic 0 up, Ecliptic 90 left, which is ~160 degree rotation from the old chart. The SVG doesn't show current positions since useless at this scale, or at least if labeled. I won't put in article for now, since orientation not consistent with close up image.
Strangely, my browser shows the original SVG [41] with a black background, but Wiki rendering has transparent background. I admit black background isn't clearly desirable anyway. Tom Ruen (talk) 08:32, 14 April 2018 (UTC)
This is my one of first posts, so I might get the talk page format wrong, and this post is kind of old, but I'll still respond.
I think this diagram should incorporate the two TNO's with q > 30 AU and semi-major axis > 220 AU, which are (148209) 2000 CR105 and 2015 RY245.
(semi-major axes at 227 and 221 AU respectively)
Note the difference between 2015 RY245 and 2015 RX245. (They are different objects.)
I believe RY245 is the object "os513" seen here. https://twitter.com/astrokiwi/status/994983595835056136
2015 RY245, like 2015 GT50, is one of those "weird" objects. Ardenau4 (talk) 23:01, 2 June 2018 (UTC)
Edit: Apparently the MPC has the semi-major axes of CR105 and RY245 at 220 and 223 AU.
I also forgot to mention (82158) 2001 FP185 (a = 226 AU, the article lists it as an SDO) Ardenau4 (talk) 23:22, 2 June 2018 (UTC)
New eTNO
15 eTNOs (including uo5m93) with hypothetical P9
I expect more data will show up soon at minor planet center
Looking at the diagram its longitude perihelion is between 2015 GT50 and 2015 KG163, and trying to visualize where it would fit in the diagram on the main page at aphelion its orbit would be close to tangent to Planet Nine's orbit, interesting. Agmartin (talk) 20:06, 11 May 2018 (UTC)
I'll update an orbital diagram when it is official. Will it get a name soon? I assume it'll be on this list when it's registered. [43]Tom Ruen (talk) 16:49, 3 June 2018 (UTC)
I was wondering why most of the objects haven't shown up at the minor planet cener, perhaps they are waiting for more papers to be accepted first. Agmartin (talk) 15:36, 4 June 2018 (UTC)
A paper will be out soon at arXiv, DISCOVERY AND DYNAMICAL ANALYSIS OF AN EXTREME TRANS-NEPTUNIAN OBJECT WITH A HIGH ORBITAL INCLINATION. The referenced eTNO 2015 BP519, [44] was the one nicknamed Caju. Tom Ruen (talk) 19:32, 9 May 2018 (UTC)
We report the discovery and dynamical analysis of 2015 BP519, an extreme Trans-Neptunian Object detected by the Dark Energy Survey at a heliocentric distance of 55 AU and absolute magnitude Hr=4.3. The current orbit, determined from an 1110-day observational arc, has semi-major axis a ≈ 450 AU, eccentricity e ≈ 0.92, and inclination i ≈ 54 degrees.
Juliette wrote "We have a few more extreme objects in the pipeline, and I'll send you an email once they pass our internal checks and we can release them!" Tom Ruen (talk) 20:05, 9 May 2018 (UTC)
It's 'pe82' that perhaps shouldn't be in the table at 'Hypothesis and the calculated effects/Extreme trans-Neptunian objects'. While Caju is now well-documented, the fact that pe82 was found by the DES is not stated in the Powerpoint referenced (Juliette Becker's slides to her talk), and in fact it does not appear to be referenced anywhere else. It appears in the figures in the slides, but nothing is said about it. Assscroft (talk) 00:54, 5 June 2018 (UTC)
Perhaps <!-- comment out-->? In private email, Becker said "Yes, (stri)pe82 (not its identifier - just an internal name since it was found in Stripe 82 of our survey) is also hopefully forthcoming, once we recover the last few observations of it! It's not as exciting as Caju (it's pretty low inclination)." Tom Ruen (talk) 01:23, 5 June 2018 (UTC)
There was an additional object (ws301y4a) in one of the graphics in this guest blog by Stephanie Hamilton over at the Planetary Society blog. It may be the same object. Agmartin (talk) 16:40, 5 June 2018 (UTC)
Seems likely. Also here [45], says " 6 Nov 2017 "We have not published their elements yet, but we hope to submit a paper soon, after which we'll publish those objects" Tom Ruen (talk) 17:07, 5 June 2018 (UTC)
Another model using collective gravity
Some recentarticles have been discussing a new model by Madigan, Fleisig, and Zderic (iPoster from recent AAS metting here) that use the collective gravity of many small objects to detach the orbits of larger objects like Sedna. This occurs occasionally when the orbits of a group of the objects cluster on one side of the solar system. This model explains the detachment of the objects' orbits, but not alignment, and like the inclination instability requires a sizable mass. Agmartin (talk) 17:04, 6 June 2018 (UTC)
Details are scarce, it appears to be a similar mechanism but in simulations with a small number of objects. I have my doubts that it works with a larger number of objects. Agmartin (talk) 18:36, 16 June 2018 (UTC)
So far it appears to be something interesting that occurred in their simulations that they presented at a conference, plus a press release by their university. Nothing published yet with more details. Agmartin (talk) 18:34, 16 June 2018 (UTC)
The Secular Dynamics of TNOs and Planet Nine Interactions
Paper on arxiv by Gongjie Li, Samuel Hadden, Matthew Payne, Matthew J. Holman.
"We find that a large number of TNOs could survive outside of mean motion resonances at 4Gyr, which differs from previous results obtained in the exact coplanar case with Neptune being treated as a quadrupole potential. In addition, secular dynamics leads to the orbital clustering seen in N-body simulations. We find that a near coplanar Planet Nine can flip TNO orbital planes, and when this happens, the geometrical longitudes of pericenter of the TNOs librate around 180∘ during the flip. Orbital precession caused by the inner giant planets can suppress the flips while keeping the longitude of pericenter librating when 30≲rp≲80 AU & a≳250 AU. This results in the alignment of the pericenter of the low inclination TNOs (i≲40∘)." Agmartin (talk) 17:25, 20 June 2018 (UTC)
ON THE INSENSITIVE USE OF THE TERM "PLANET 9" FOR OBJECTS BEYOND PLUTO
We the undersigned wish to remind our colleagues that the AU planet definition adopted in 2006 has been controversial and is far from universally accepted. Given this, and given the incredible accomplishment of the discovery of Pluto, the harbinger of the solar system's third zone - the Kuiper Belt - by planetary astronomer Clyde W. Tombaugh in 1930, we the undersigned believe the use of the term "Planet 9" for objects beyond Pluto is insensitive to Professor Tombaugh's legacy.
We further believe the use of this term should be discontinued in favor of culturally and taxonomically neutral terms for such planets, such as Planet X, Planet Next, or Giant Planet Five.
I received an email on July 31, 2018 (from Astronomy magazine?) stating that a team led by Mike Brown has submitted a paper announcing the discovery of (a) Planet Nine. As such things go, astronomers need to confer to assure they have their "ducks in line" before sharing details with the general public. The authors bemoaned the difficulty of having a submission peer reviewed in August. Publication will follow; the team hopes that this will occur in August 2018. At that point, the general public will have whatever details are in this paper. Assuming confirmation, an informal nickname will follow; then, eventually, an official name. Confirmation by the James Webb Space Telescope will have to wait until a few [perhaps several] months after its launch, currently slated for Spring 2021.
2602:304:B190:1550:D481:93FB:BEE8:7D1A (talk) 15:27, 3 August 2018 (UTC) Robert Gorby
2602:304:B190:1550:D481:93FB:BEE8:7D1A (talk) 15:27, 3 August 2018 (UTC) 8/3/2018 8:25 AM PDT
In this paper we study the possibility that lower perihelion distances for the additional planet can lead to angular confinements as observed in the population of objects with semimajor axes greater than 250 au and perihelion distances higher than 40 au...
Our investigations showed that lower perihelion distances from the outer planet usually lead to more substantial confinements than higher ones, while retaining the Classical Kuiper Belt as well as the ratio of the number of detached with perihelion distances higher than 42 au to scattering objects in the range of semimajor axes from 100 au to 200 au.
In a nutshell Gomez et al proposing lower perihelion (closer to 100 AU) and same aphelion; so higher eccentricity. This reproduces the observed twin clustering of eTNOs & also Kuiper Cliff J mareeswaran (talk) 18:34, 7 August 2018 (UTC)
They included some analysis of what happens inside 50 AU, I wonder what happens beyond that. I expect the data from OSSOS and the number of SDOs they found in resonances will have something to say about it. Agmartin (talk) 17:58, 8 August 2018 (UTC)
Both Mike Brown and Konstantin Batygin have tweeted to refute the element of the much-copied WaPo/Quanta story that Planet Nine might be invisible being beyond 1000AU:
A few news articles have popped up about Planet Nine over the last few days. To set the record straight: no P9 is not hiding, it’s not invisible, and it’s not going to destroy the Earth. It’s dim, but within our grasp - the beauty of the P9 theory is that it’s directly testable.
Batygin adds the caveat that Planet Nine can be spotted by optical telescopes, even if it is beyond 1000 AU, IF its radius is 4 times that of Earth's J mareeswaran (talk) 07:18, 4 September 2018 (UTC)
Is the Subaru Telescope the only telescope being used to search for it? Searching in infrared only? If not the only telescope, we should add them to the pertinent section. Thanks, Rowan Forest (talk) 17:26, 5 September 2018 (UTC)
It is the telescope that Brown&Batygin are using. Since they are the only team who are both able and willing to spend large amounts of observing time from a multi-meter telescope on it, Subaru is the only telescope used for the search. There's really no other telescope in the world that could compete with Suprime-Cam, anyway.Renerpho (talk) 05:14, 6 September 2018 (UTC)
I looks like something different since BICEP3 is collecting data and CMB-S4 is planned for 2020 and after and at multiple sites according to its webpage, though looking at this page it might be include upgrades of existing sites. Agmartin (talk) 17:01, 5 September 2018 (UTC)
Detection using millimeter wave radiation ?
One idea is to look for the heat glow the body should emit directly. Luhman essentially ruled out the existence of anything bigger and warmer than a gas giant with a 2014 analysis of infrared data, but physicists expect a smaller, colder Planet Nine to shine in the millimeter part of the spectrum.
Current millimeter telescopes in Antarctica and Chile could detect Planet Nine today should it stray across their search field, according to Gilbert Holder, a cosmologist at the University of Illinois. Yet those instruments are busy mapping the cosmic microwave background (CMB), so they’re not necessarily pointed in the right direction at the right times. Holder is waiting for the Next Generation CMB Experiment, which his preliminary calculations estimate could pick up a planet as small as Earth at 1,000 AU. — why so shy planet nine?
An abstract from the upcoming DPS Meeting mentions object with a = 1190 AU q = 65 AU longitude of perihelion similar to Sedna and 2012 VP113. Agmartin (talk) 21:58, 11 September 2018 (UTC)
Probably updated semimajor axis for gna, I'd wait till there was some mention in the press before adding it to the table. Agmartin (talk) 16:13, 12 September 2018 (UTC)
Agmartin (talk) 18:05, 13 September 2016 (UTC)
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![[3]](http://www.astrobio.net/wp-content/uploads/2016/08/NewExtremes5-1050x751.jpg){kind=link}
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![[12]](http://www.sciencemag.org/sites/default/files/styles/inline__699w__no_aspect/public/OrbitGraphic.png){kind=link}
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![[20]](https://upload.wikimedia.org/wikipedia/commons/archive/3/39/20170619212340%21Poles_of_Extreme_TNOs.png){kind=link}
![[41]](https://upload.wikimedia.org/wikipedia/commons/7/76/Planet_nine_etnos.svg){kind=link}
