Talk:(725095) 2008 TN208

Preliminary consultation

@Rontombontom and @Kheider

What's up with 2010 GZ60 (K10G60Z)? The recently released MPEC 2018-D36 : DAILY ORBIT UPDATE (2018 FEB. 21 UT) gives an e=0.24 and a=0.87 which translates into an orbit in the range of 0.66–1.09 AU (q–Q), and qualifies for an classification as ATE/PHA as currently displayed in the MPC-object view. Where does the statement that is an estimated main-belt asteroid come from? The data on JPL (below) and the CNEOS-cites in the lead do not make that statement either.

Based on the current jpldata, 2010 GZ₆₀ is an unclassified asteroid (see footnote b), and not a main-belt asteroid either, as it has a semi-major axis too large to be an MBA, and an eccentricity too high to be a JT. It also has a Jupiter tisserand of a JFC rather than an asteroid, and qualifies as a Jupiter-crosser. Of course, the jpldata seems to be outdated.

However the recent changes in this article do not reflect my interpretation. What am I missing? Thx, Rfassbind – talk 13:42, 1 March 2018 (UTC)

It is really just a numbers game. MBAs are by far the most numerous discovered objects in the solar system and account for 94% of all known Small Solar System bodies. Of the 755k known minor planets, 711k are MBAs (inner+core+outer). I had noticed the 2018 MPC solution, but it looks dubious as they are suggesting it was discovered near aphelion (0.26AU from Earth and 1.06AU from the Sun) which is quite unlikely and deviates significantly from their 2017 MPC solution which suggested perihelion around 1.3AU. But it is to be expected for an object with a 1-day observation arc to generate radically different nominal solutions. Unfortunately the MPC does not even list uncertainties in their solution. JPL used 14 of the 15 observations, while the MPC used only 12 of the 15 observations in their solution. The JPL solutions seem more consistent. The JPL solution is not too far removed from objects such as outer MBA 2015 CD60. -- Kheider (talk) 15:38, 1 March 2018 (UTC)

Thx for the insight. The last sentence in the lead qualifies for both original research and editorial synthesis and should be removed. Don't you think? To me, only the MPC is up-to-date and 2010 GZ₆₀ might be well relisted on the Sentry Risk Table. Best, Rfassbind – talk 02:31, 2 March 2018 (UTC)

With the odds of impact previously being 1 in millions, the nominal orbit will need to migrate inwards to be relisted. You do know that JPL downloads the observations directly from the MPC. To claim the JPL solution (dated 2018-Feb-21) is not up to date is bizarre. Since JPL is using more observations in their solution (14 vs 12), it is fair to say their solution is a better fit to the available data. -- Kheider (talk) 02:56, 2 March 2018 (UTC)

Only now is the MPC up to date and they list it as a MBA. Link for me to look at later. -- Kheider (talk) 16:46, 7 March 2018 (UTC)

I don't now have the time to look into the subject of this dispute deeper, but the use of 14 vs 12 observations probably has to do with two near-simultaneous observations at 2010 04 06.116 respectively 2010 04 06.976, so I don't think using 14 makes the JPL solution any better. Rontombontom (talk) 00:06, 12 March 2018 (UTC)

Two observations close to one another should be fairly easy to fit. Generally a solution that fits more observations will be better. Most of the "dispute" was from when the MPC was using a poor solution that has been updated. JPL is the only solution that lists uncertainties. -- Kheider (talk) 01:11, 12 March 2018 (UTC)