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J1407b

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J1407b

ALMA radio image of V1400 Centauri and a nearby object, which might be J1407b[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Centaurus
Right ascension 14h 07m 47.92976s[2]
Declination −39° 45′ 42.7671″[2]
Details
Mass<6[1]: 2  MJup
Database references
SIMBADdata

J1407b is a substellar object, either a free-floating planet or brown dwarf, with a massive circumplanetary disk or ring system. It was first detected by automated telescopes in 2007 when its disk eclipsed the star V1400 Centauri, causing a series of dimming events for 56 days. The eclipse by J1407b was not discovered until 2010, by Mark Pecaut and Eric Mamajek, and was announced in 2012. J1407b's disk spans a radius of about 90 million kilometers (56 million miles) and consists of many rings and gaps which may indicate moons are forming in orbit around the object. It was initially thought to be orbiting V1400 Centauri, but later studies suggest J1407b is likely an unbound object that coincidentally passed in front of the star. J1407b may have been observed via high-resolution imaging in 2017, which may suggest the object is less than 6 Jupiter masses.[1]

2007 eclipse and discovery

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Visual-band light curve of V1400 Centauri, showing the 2007 eclipse. The main plot shows the SuperWASP data.[3] The inset plot, adapted from Mamajek et al.,[4] shows the data near mid-eclipse. The purple markers show the pairs of small brightness dips due to eclipses by rings.
Artist's impression of a circumstellar disk eclipsing a star, similar to J1407b's eclipse of V1400 Centauri in 2007

During 7 April to 4 June 2007,[a] telescopes of the Super Wide Angle Search for Planets (SuperWASP) and All Sky Automated Survey (ASAS) projects automatically recorded V1400 Centauri undergoing a series of significant dimming events for 56 days.[7] The pattern of these dimming events was complex yet nearly symmetrical, indicating they were caused by an opaque, disk-like structure eclipsing the star. The light curve of V1400 Centauri during 2007 showed at least five major dimming events, including one long and very deep central eclipse bracketed by two pairs of shorter eclipses symmetrically occurring 12 days and 26 days before and after the middle of the deep eclipse.[4]: 5  The deep eclipse lasted about 14 days and blocked out at least 95% of V1400 Centauri's light, causing it to dim by at least 3.3 magnitudes.[4]: 1 [b] The short eclipses before and after the deep eclipse blocked out at least 60% of the star's light, causing it to dim by at least 1 magnitude.[4]: 1 [b]

The event was not noticed until 3 December 2010,[4]: 5  when Mark J. Pecaut, a graduate student of Eric E. Mamajek at the University of Rochester, discovered V1400 Centauri's 2007 eclipse while investigating SuperWASP's public light curve database.[8][9] Pecaut and Mamajek were originally intending to use the SuperWASP data to check for brightness variability in candidate low-mass stars of the Scorpius–Centaurus association, which they had been studying since 2009.[10][4]: 4  Mamajek, Pecaut, and collaborators presented their discovery of V1400 Centauri's eclipse in January 2012 at the 219th American Astronomical Society conference in Austin, Texas,[11][10] and then formally published their results in The Astronomical Journal in March 2012.[4]

Unsuccessful searches for companions around V1400 Centauri suggest that the object that eclipsed the star must be substellar in mass (below 80 Jupiter masses), which means it could either be a brown dwarf or a planetary-mass object.[12]: 423  Mamajek's team hypothesized that this substellar object could be orbiting V1400 Centauri as either an exoplanet or binary companion, although later studies have since disfavored this scenario.[4]: 10–11 [1]

Name

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The object was first dubbed "J1407b" in a paper published by Tim van Werkhoven, Matthew Kenworthy, and Eric Mamajek in 2014, which assumed the object was orbiting V1400 Centauri as an exoplanet.[5] The name J1407b follows the exoplanet naming convention by adding the letter "b" after the host star's name.[5] At the time of J1407b's discovery, V1400 Centauri was known as "J1407", which is the shortened form of the star's full SuperWASP catalogue designation 1SWASP J140747.93–394542.6.[4]: 5  This designation shows the star's location in the sky in equatorial coordinates.[13]

Disk properties and potential exomoons

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Simulation of J1407b eclipsing V1400 Centauri during 2007. The light curve plot below illustrates V1400 Centauri's brightness changes during the eclipse. The ring structure of J1407b and the orange light curve represents a best-fit model to SuperWASP's photometric data, which are shown in yellow points.

J1407b's disk may be considered a circumplanetary disk[4]: 9 [14][15]: 1683–1684  or a massive ring system composed of mainly dust.[16][1] The rate of V1400 Centauri's dimming during J1407b's eclipses indicates that J1407b and its disk were moving at a transverse velocity of 35 km/s (22 mi/s) relative to the star,[1]: 5  which corresponds to a radius of 0.6 astronomical units (90 million km; 56 million mi) between J1407b and its disk's outer edge.[5]: 2850  To compare, the radius of J1407b's disk is roughly 200 times larger than that of Saturn's E Ring,[c] and lies between the orbital radii of Mercury (0.39 AU) and Venus (0.72 AU).[18] J1407b's circumplanetary disk or ring system has been frequently compared to that of Saturn's, which has led popular media outlets to dub it a "Super Saturn"[19][20] or a "Saturn on steroids".[10][21]

The radius of the disk extends far beyond J1407b's Roche limit at 0.001 AU (150 thousand km; 93 thousand mi), which allows exomoons (or exoplanets if J1407b is a brown dwarf) to form within the disk, as evidenced by gaps seen in J1407b's disk.[15]: 1682  J1407b's disk is tilted by 13° relative to the plane of J1407b's path and Earth's line of sight, which explains its nearly-symmetrical eclipse light curve and differing time durations between eclipse ingress and egress.[4]: 12 [5]: 2846  Variations in V1400 Centauri's dimming rate during the eclipses suggest that J1407b's disk has a height-to-radius ratio of approximately 0.0015, which corresponds to a vertical disk thickness of 0.0009 AU (130 thousand km; 84 thousand mi).[5]: 2850 [d]

The varying depths of J1407b's eclipses indicate its disk consists of various concentric rings and gaps of different opacities. A 2015 analysis of J1407b's eclipse light curve by Kenworthy and Mamajek found that J1407b's disk comprises at least 37 distinct rings with radii ranging from 0.2 to 0.6 AU (30 to 90 million km; 19 to 56 million mi).[14]: 1, 5 [7]: 1  The innermost ring of J1407b's disk extends out to a radius of 0.206 AU (30.8 million km; 19.1 million mi) and is the most opaque region of the disk.[14]: 9  Assuming the rings have a mass density proportional to their opacity, the total mass of J1407b's disk is roughly 100 lunar masses (1.23 Earth masses).[14]: 9 [15]: 1686 

J1407b's disk has a 4-million km (2.5-million mi)-wide gap between radii 0.396 to 0.421 AU (59.2 to 63.0 million km; 36.8 to 39.1 million mi), which is believed to have been created by a nearly-Earth-sized (<0.8 M🜨) exomoon orbiting within that gap and clearing out material, in a similar fashion to the shepherd moons of Saturn's rings.[14]: 7 [15]: 1682  Another smaller, 1-million km (0.62-million mi)-wide gap in J1407b's disk between radii 0.354 to 0.360 AU (53.0 to 53.9 million km; 32.9 to 33.5 million mi) is also believed to have been created by an exomoon orbiting inside that gap.[14]: 8 [15]: 1683–1684  Other possible mechanisms for creating J1407b's disk gaps, such as orbital resonances between multiple exomoons, are deemed unlikely because they cannot produce other observed features of J1407b's disk.[15]: 1684  Altogether, the presence of rings and gaps outside J1407b's Roche limit combined with evidence of possible exomoons suggests that J1407b's disk is currently in the process of accreting into more exomoons, and will eventually become a satellite system (or a planetary system if J1407b is a brown dwarf) in less than a few billion years.[14]: 9 [15]: 1682 

Bound companion hypothesis

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Mamajek's team initially considered the bound companion hypothesis plausible because V1400 Centauri is young enough that a protoplanetary disk could hypothetically exist around the star and its putative companion, and there are known eclipsing binary stars where one component is surrounded by a circumstellar disk (for example Epsilon Aurigae).[4]: 8  Although it is now considered obsolete, the hypothesis of J1407b being a substellar companion or exoplanet orbiting V1400 Centauri was popularized by Mamajek and Kenworthy in 2015, when they announced their research on J1407b in a press release published by their respective universities.[22][23]

Proposed orbit

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Diagram of the hypothesized V1400 Centauri planetary system, with J1407b's circumplanetary disk shown to scale. The range of possible elliptical orbits for J1407b is shown in red.

Following the assumption that J1407b is orbiting V1400 Centauri, its transverse speed of 35 km/s (22 mi/s) during the 2007 eclipse should be the same as its orbital speed around the star. This orbital speed allows for a range of possible orbital periods depending on J1407b's orbital eccentricity: if J1407b has a circular orbit with a constant orbital speed, then it would have an orbital period around 200 days, whereas if J1407b's orbit is more elliptical with a varying orbital speed, then it could have longer orbital periods of up to several years.[4]: 8 

Continuous observations of V1400 Centauri's brightness after 2007 did not show any signs of eclipse-like dimming, which rules out the possibility of near-circular and short-period orbits for J1407b.[14]: 9  A more extensive analysis of V1400 Centauri's brightness in archival observations from 1890 to 1990 similarly found no signs of eclipses, ruling out 90% of possible orbital periods between 10 and 20 years for J1407b.[24]: 6–7  Although these observations do not rule out the possibility of orbital periods longer than 25 years, such long orbital periods are considered unlikely because they require an extremely eccentric orbit for J1407b, which would destabilize J1407b's disk.[24]: 6–7  Overall, these constraints suggest a probable orbital period range of 14–17 years (with the most probable orbital periods around 16.5–17 years) if J1407b orbits V1400 Centauri.[24]: 6  For this orbital period range, J1407b's orbital eccentricity must be between 0.72 and 0.78.[24]: 7 

The V1400 Centauri planetary system[5]: 2846 [16]: 1 [24]: 6–7 
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b (disputed) 5–20[24]: 7  MJ >5.0±0.1 AU
(for >11 yr orbital period)[16]: 1  		14–17 yr
(5110–6200 d)[24]: 6–7  		0.72–0.78
[24]: 7  		89.995° —

Problems with the hypothesis

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A 2016 study by Steven Rieder and Matthew Kenworthy investigated the orbital dynamics of J1407b's postulated eccentric orbit and found that the disk of J1407b either fills a large fraction of or extends beyond J1407b's Hill radius (extent of J1407b's gravitational influence against V1400 Centauri) regardless of its mass, which meant that J1407b's disk could be easily destabilized by V1400 Centauri's gravitational influence whenever it makes its closest approach to the star at periapsis.[16]: 2  To remedy the issue with J1407b's disk stability in an eccentric orbit, Rieder and Kenworthy proposed that J1407b must be a brown dwarf of at least 20 Jupiter masses (MJ) and its disk must orbit J1407b in retrograde motion, opposite to the direction J1407b orbits its host star.[16]: 3–4  A retrograde-orbiting disk would survive longer against V1400 Centauri's gravitational influence, although it would still slowly shrink over timescales of 10,000 years.[16]: 4  Rieder and Kenworthy suggested that the lifetime of a retrograde-orbiting disk could be prolonged by dust-producing processes such as tidal disruption of comets around J1407b.[16]: 4  A 2018 study found that a lower mass of 5–20 Jupiter masses would be marginally consistent with the observations.[24]: 1,7 [25]

Despite the better stability of a retrograde-orbiting disk, it could not explain why J1407b's disk is flat and tilted relative to its postulated orbit around V1400 Centauri.[8] The star's gravitational influence is strong enough to realign J1407b's disk to its orbital plane instead of J1407b's equator, which would result in significant warping of J1407b's disk.[8] In addition to this issue, the origin of a retrograde-orbiting disk together with J1407b's postulated eccentric orbit could not be easily explained by current theories for planetary formation.[16]: 5  If J1407b is a companion that formed in orbit around V1400 Centauri, then its disk is expected to be prograde, orbiting J1407b in the same direction as its orbit around the star.[16]: 5 

One hypothesis to explain J1407b's supposed eccentric orbit proposes that V1400 Centauri could have another undetected substellar companion that is orbiting beyond J1407b and gravitationally perturbing its orbit.[7]: 2  However, the existence of additional substellar companions beyond the distance of J1407b's supposed orbit had already been shown to be unlikely by Mamajek's team, who attempted a search for J1407b using various telescopes during 2012–2013.[12]: 412  High-resolution imaging of V1400 Centauri in near-infrared light found no signs of J1407b or any brown dwarf-mass companions within a few AU from the star.[12]: 414–415  Doppler spectroscopy of V1400 Centauri showed no evidence of radial velocity variations that would be caused by a >12 MJ companion orbiting the star.[12]: 422  Furthermore, continuous observations of V1400 Centauri's brightness over a 19-year timespan between 2001 and 2020 found no evidence of transits by Jupiter-sized exoplanets or substellar companions before and after J1407b's 2007 eclipse.[7]: 2  Overall, the lack of recurring eclipses, non-detections of orbiting companions, and complications in explaining J1407b's eccentric orbit and disk stability suggest that J1407b likely does not orbit V1400 Centauri and is instead a free-floating object.[24]: 1 [1]: 2 

Unbound object hypothesis

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ALMA radio image of V1400 Centauri and the nearby object, which might be J1407b
Artist's impression of OTS 44, a young brown dwarf surrounded by a dusty circumplanetary disk. J1407b most likely resembles this if it is a free-floating young substellar object.

In a 2015 study, Mamajek and Kenworthy initially rejected the idea of J1407b being a free-floating object because they thought it was unlikely. Their reasoning was that stars and other interstellar objects are typically separated extremely far apart from each other (projected distance ~1,000 AU), so the probability of two unbound objects coincidentally being aligned in Earth's line of sight and eclipsing one another is extremely small.[14]: 9  They further argued that the existence of J1407b's massive disk implies that the object must be considerably younger than the stars surrounding its location, which makes it difficult to explain J1407b's origin.[14]: 9  However, they eventually reconsidered their stance on J1407b's nature as they uncovered issues with the bound companion hypothesis.[1]

ALMA observations

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In 2017, Kenworthy and collaborators conducted a search for J1407b using the Atacama Large Millimeter Array (ALMA), which is capable of detecting thermal radiation from ringed substellar objects in millimeter radio frequencies.[1]: 2  High-resolution radio images from ALMA showed no evidence of bound companions within 100 milliarcseconds (mas) from the star, but did detect a nearby object 438±8 mas away from V1400 Centauri's observed position.[1]: 3–4  At V1400 Centauri's distance from Earth, this angular separation corresponds to a projected distance of 61 AU, which is too far away from the star to match the proposed orbit for J1407b.[1]: 3–4  The observed angular separation is marginally consistent with the expected distance (543±82 mas) travelled by an unbound object moving at J1407b's transverse velocity during 2007–2017, which makes it possible that the ALMA object could be J1407b if it is a free-floating object.[1]: 3  If the ALMA source is J1407b, it would have a proper motion of 43 mas/year.[1]: 3  The thermal emission brightness of the ALMA object is also consistent with it being a substellar object surrounded by a warm disk of submillimeter-sized dust particles, further supporting the possibility that it could be J1407b.[1]: 1, 4 

In 2019, Kenworthy and collaborators attempted a follow-up search for J1407b using high-resolution imaging by the Very Large Telescope.[1]: 2  These images, which were taken in near-infrared light, did not detect the ALMA object and showed no signs of >6 MJ substellar objects beyond 30 AU (0.25 arcseconds) nor >4 MJ objects beyond 100 AU (0.70 arcseconds) from V1400 Centauri.[1]: 3  [1]: 2  These non-detections in near-infrared wavelengths place an upper mass limit of <6 MJ for the ALMA object, which would make it a sub-brown dwarf or a rogue planet since it lies below the 13 MJ threshold for brown dwarfs.[1]: 2  It is possible that the ALMA object could be a young ejected planet, although if it is J1407b, then its transverse velocity would suggest that it did not originate from the Scorpius–Centaurus association.[1]: 1, 4 

While the properties of the ALMA object appear to match those of J1407b, it has only been observed once, so it is not yet confirmed whether it is moving in the right direction and speed.[1]: 5  It is possible that the ALMA object could be a stationary background galaxy or a spurious detection caused by image noise, although these two possibilities are considered unlikely.[1]: 5  ALMA reobserved V1400 Centauri in June and July 2024, which will provide confirmation of the object's nature once the data is analyzed and published.[26]

See also

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Notes

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  1. ^ According to van Werkhoven et al. (2014), J1407b's eclipse start and end times are Modified Julian Date (MJD) 54197 and 54255, respectively.[5]: 2847  To convert these to Julian date (JD), add 2400000.5 to MJD. This gives JD 2454197.5 and JD 2454255.5 for the eclipse start and end times, respectively. Converting these JD dates to calendar dates gives 7 April 2007 UTC and 4 June 2007 UTC, respectively.[6]
  2. ^ a b The magnitude difference of two different flux (brightness) values is given by the equation Δm = –2.5log(F2/F1). In the context of V1400 Centauri, F1 is its pre-eclipse brightness and F2 is its mid-eclipse brightness. The ratio of brightnesses F2/F1 represents how much the star dimmed relative to its pre-eclipse brightness. Rearranging the equation for F2/F1 gives F2/F1 = 10–Δm/2.5. For the Δm = 3.3 deep eclipse, V1400 Centauri dimmed to roughly F2/F1 = 5% of its pre-eclipse brightness (or 95% of its light blocked). For the Δm = 1.0 eclipse, V1400 Centauri dimmed to roughly F2/F1 = 40% of its pre-eclipse brightness (or 60% of its light blocked). These calculations can be verified by looking at the normalized flux plot shown in Figure 6 of van Werkhoven et al. (2014).[5]: 2849 
  3. ^ The outer edge of Saturn's E Ring is approximately 480,000 km (300,000 mi) in radius from Saturn.[17] For J1407b, the outer edge of its circumplanetary disk is 90 million km (56 million mi) in radius,[14] which is approximately 188 times that of Saturn's E Ring.
  4. ^ Multiplying J1407b's disk radius (r = 0.6 AU by the height-to-radius ratio h/r = 0.0015 gives h = 0.0009 AU for height.

References

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  1. ^ a b c d e f g h i j k l m n o p q r s t u Kenworthy, M. A.; Klaasen, P. D.; Min, M.; van der Marel, N.; Bohn, A. J.; Kama, M.; et al. (January 2020). "ALMA and NACO observations towards the young exoring transit system J1407 (V1400 Cen)". Astronomy & Astrophysics. 633: 6. arXiv:1912.03314. Bibcode:2020A&A...633A.115K. doi:10.1051/0004-6361/201936141. A115.
  2. ^ a b "[KLK2015] J1407b". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 July 2024.
  3. ^ "Search SuperWASP Time Series". NASA Exoplanet Archive. NASA. Archived from the original on 27 November 2022. Retrieved 27 November 2022. (In the "Include location search around coordinates / object names" box, type "V1400 Centauri" and then click "Submit Search".)
  4. ^ a b c d e f g h i j k l m Mamajek, Eric E.; Quillen, Alice C.; Pecaut, Mark J.; Moolekamp, Fred; Scott, Erin L.; Kenworthy, Matthew A.; et al. (March 2012). "Planetary Construction Zones in Occultation: Discovery of an Extrasolar Ring System Transiting a Young Sun-like Star and Future Prospects for Detecting Eclipses by Circumsecondary and Circumplanetary Disks". The Astronomical Journal. 143 (3): 15. arXiv:1108.4070. Bibcode:2012AJ....143...72M. doi:10.1088/0004-6256/143/3/72. S2CID 55818711. 72.
  5. ^ a b c d e f g h van Werkhoven, T. I. M.; Kenworthy, M. A.; Mamajek, E. E. (July 2014). "Analysis of 1SWASP J140747.93-394542.6 eclipse fine-structure: hints of exomoons". Monthly Notices of the Royal Astronomical Society. 441 (4): 2845–2854. Bibcode:2014MNRAS.441.2845V. doi:10.1093/mnras/stu725.
  6. ^ "JD Date/Time Converter". Solar System Dynamics. JPL/NASA. Retrieved 25 July 2024.
  7. ^ a b c d Barmentloo, S.; Dik, C.; Kenworthy, M. A.; Mamajek, E. E.; Hambsch, F.-J.; Reichart, D. E.; et al. (August 2021). "A search for transiting companions in the J1407 (V1400 Cen) system". Astronomy & Astrophysics. 652: 8. arXiv:2106.15902. Bibcode:2021A&A...652A.117B. doi:10.1051/0004-6361/202140768. S2CID 235683556. A117.
  8. ^ a b c Kenworthy, Matthew A. (27 July 2024). "J1407b". Archived from the original on 28 July 2024. Retrieved 28 July 2024.
  9. ^ "Scientists discover a Saturn-like ring system eclipsing a Sun-like star". Astronomy. 13 January 2012. Archived from the original on 20 May 2024. Retrieved 5 September 2024.
  10. ^ a b c Choi, Charles Q. (12 January 2012). "'Saturn on Steroids': 1st Ringed Planet Beyond Solar System Possibly Found". Space.com. Archived from the original on 29 November 2023. Retrieved 24 July 2024.
  11. ^ Mamajek, Eric E.; Quillen, A. C.; Pecaut, M.; Moolekamp, F.; Scott, E. L.; Kenworthy, M. A.; et al. (January 2012). Planetary Construction Zones in Occultation: Eclipses by Circumsecondary and Circumplanetary Disks and a Candidate Eclipse of a Pre-Main Sequence Star in Sco-Cen. 219th AAS Meeting. Austin, Texas: American Astronomical Society. Bibcode:2012AAS...21940404M. 404.04. Retrieved 12 July 2024.
  12. ^ a b c d Kenworthy, M. A.; Lacour, S.; Kraus, A.; Triaud, A. H. M. J.; Mamajek, E. E.; Scott, E. L.; et al. (January 2015). "Mass and period limits on the ringed companion transiting the young star J1407". Monthly Notices of the Royal Astronomical Society. 446 (1): 411–427. arXiv:1410.6577. Bibcode:2015MNRAS.446..411K. doi:10.1093/mnras/stu2067.
  13. ^ "V* V1400 Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 May 2024.
  14. ^ a b c d e f g h i j k Kenworthy, M. A.; Mamajek, E. E. (February 2015). "Modeling giant extrasolar ring systems in eclipse and the case of J1407b: sculpting by exomoons?". The Astrophysical Journal. 800 (2): 10. arXiv:1501.05652. Bibcode:2015ApJ...800..126K. doi:10.1088/0004-637X/800/2/126. S2CID 56118870. 126.
  15. ^ a b c d e f g Sutton, P. J. (June 2019). "Mean motion resonances with nearby moons: an unlikely origin for the gaps observed in the ring around the exoplanet J1407b". Monthly Notices of the Royal Astronomical Society. 486 (2): 1681–1689. arXiv:1902.09285. Bibcode:2019MNRAS.486.1681S. doi:10.1093/mnras/stz563. S2CID 119546405.
  16. ^ a b c d e f g h i Rieder, Steven; Kenworthy, Matthew A. (November 2016). "Constraints on the size and dynamics of the J1407b ring system". Astronomy & Astrophysics. 596: 5. arXiv:1609.08485. Bibcode:2016A&A...596A...9R. doi:10.1051/0004-6361/201629567. S2CID 118413749. A9.
  17. ^ Williams, David R. (19 April 2022). "Planetary Fact Sheet - Metric". NASA Goddard Space Flight Center. NASA. Retrieved 24 July 2024.
  18. ^ Williams, David R. (22 March 2024). "Planetary Fact Sheet - Metric". NASA Goddard Space Flight Center. NASA. Retrieved 24 July 2024.
  19. ^ Hall, Shannon (3 February 2015). "This Super-Saturn Alien Planet Might Be the New 'Lord of the Rings'". Space.com. Archived from the original on 4 June 2023. Retrieved 24 July 2024.
  20. ^ Winder, Jenny (27 February 2024). "The story of J1407b, the first exoplanet discovered with a ring system like Saturn". BBC Sky at Night Magazine. BBC. Archived from the original on 11 June 2024. Retrieved 23 July 2024.
  21. ^ St. Fleur, Nicholas (13 October 2016). "Distant Ringed Object Could Be 'Saturn on Steroids'". New York Times. Archived from the original on 20 May 2018. Retrieved 14 October 2016.
  22. ^ Sierra, Leonor (26 January 2015). "Gigantic ring system around J1407b much larger, heavier than Saturn's". University of Rochester. Archived from the original on 25 December 2017. Retrieved 24 July 2024.
  23. ^ "Gigantic ring system discovered around exoplanet J1407b". Leiden University. 27 January 2015. Archived from the original on 18 July 2024. Retrieved 24 July 2024.
  24. ^ a b c d e f g h i j Mentel, R. T.; Kenworthy, M. A.; Cameron, D. A.; Scott, E. L.; Mellon, S. N.; Hudec, R.; et al. (November 2018). "Constraining the period of the ringed secondary companion to the young star J1407 with photographic plates". Astronomy & Astrophysics. 619: 7. arXiv:1810.05171. Bibcode:2018A&A...619A.157M. doi:10.1051/0004-6361/201834004. S2CID 55015149. A157.
  25. ^ Sutton, Phil J.; Albery, Brayden; Muff, Jake (14 March 2022). "A Self-Gravitating Exoring Around J1407b and Implications for In-Situ Exomoon Formation". Frontiers in Astronomy and Space Sciences. 9. Bibcode:2022FrASS...919933S. doi:10.3389/fspas.2022.819933. ISSN 2296-987X.
  26. ^ "ALMA Science Archive". National Radio Astronomy Observatory. Archived from the original on 24 July 2024. Retrieved 23 July 2024.
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