(523794) 2015 RR245

Trans-Neptunian object July 2016 yes (523794) 2015 RR 245 possible dwarf planet 523794-2015rr245 hst.png 2015 RR 245 imaged by the Hubble Space Telescope in October 2020 OSSOSMichele T. Bannister et al. Mauna Kea Obs. 9 September 2015 15 October 2004 (523794) 2015 RR 245 TNOSDOresonant (2:9)p-DPdistant 27 April 2019 (JD 2458600.5) 3 13.10 yr (4,786 d) 128.80 AU 33.943 AU ≈ 21 August 2092±3 days 81.373 AU 0.5829 734.05 yr (268,113 d) 323.86° 0.0013 ms / day 7.5755° 211.68° 261.02° 0 (1?) 525 km ≈630 km ≈670 km mi 2, assuming an albedo of 0.12; 500 - 870 km for an albedo of 0.21 to 0.07 0.12 (assumed)0.11 (assumed)0.135 (assumed) neutralg–r=0.59 0.11 21.2 (perihelic) 3.6 0.1 (Hr)3.81 (523794) 2015 RR 245 is a large trans-Neptunian object of the Kuiper belt in the outermost regions of the Solar System. It was discovered on 9 September 2015, by the Outer Solar System Origins Survey at Mauna Kea Observatories on the Big Island of Hawaii, in the United States. The object is in a rare 2:9 resonance with Neptune and probably measures somewhere between 500 and 900 kilometres in diameter. Discovery A first precovery of 2015 RR 245 was taken at the Cerro Tololo Observatory in Chile on 15 October 2004. It was first observed by a research team led by Michele Bannister while poring over images that the Canada–France–Hawaii Telescope in Hawaii took in September 2015 as part of the Outer Solar System Origins Survey (OSSOS), and later identified in images taken at Sloan Digital Sky Survey and Pan-STARRS between 2008 and 2016. The discovery was formally announced in a Minor Planet Electronic Circular on 10 July 2016. Numbering and naming This minor planet was numbered by the Minor Planet Center on 25 September 2018 (M.P.C. 111779). As of 2025, it has not been named. Orbit and classification thumb|upright=1.5|left|2015 RR 245 orbit diagram with the Kuiper belt and outer planet orbits shown thumb|upright=1.5|left|2015 RR 245's orbit librating in a 2:9 resonance with Neptune As of 2018, 2015 RR 245 has a reasonably well defined orbit with an uncertainty of 3. It orbits the Sun at a distance of 33.8–128.6 AU once every 731 years and 6 months (for reference, Neptune's orbit is at 30 AU). Its orbit has an eccentricity of 0.58 and an inclination of 8° with respect to the ecliptic. 2015 RR 245 is among the most distant known Solar System objects. As of 2018, it is 63 AU from the Sun. It will make its closest approach to the Sun in 2093, when it will reach an apparent magnitude of 21.2. 2:9 resonance Additional precovery astrometry from the Sloan Digital Sky Survey and the Pan-STARRS1 survey shows that 2015 RR 245 is a resonant trans-Neptunian object, securely trapped in a 2:9 mean motion resonance with Neptune, meaning that this minor planet orbits the Sun twice in the same amount of time it takes Neptune to complete 9 orbits. The object is unlikely to have been trapped in the 2:9 resonance for the age of Solar System. It is much more likely that it has been hopping between various resonances and got trapped in the 2:9 resonance in the last 100 million years. thumb|center|upright=2|Distribution of trans-Neptunian objects. Objects occupying the stronger resonances are in red. Physical characteristics Diameter and albedo Its exact size is uncertain, but the best estimate is around 670 km mi on in diameter, assuming an albedo of 0.12 (within a wider range of 500 to 870 km, based on albedos of 0.21 to 0.07). For comparison, Pluto, the largest object in the Kuiper belt, is about 2376.6 km mi on in diameter.Stern S.A. Grundy W. McKinnon W.B. Weaver H.A. Young L.A. The Pluto System After New Horizons Annual Review of Astronomy and Astrophysics 2018 357–392 1712.05669 2017 2018ARA&A..56..357S 119072504 10.1146/annurev-astro-081817-051935 0066-4146Nimmo Francis etal Mean radius and shape of Pluto and Charon from New Horizons images Icarus 2017 287 12–29 2017Icar..287...12N 1603.00821 44935431 10.1016/j.icarus.2016.06.027 Johnston's Archive gives a diameter of 500 kilometers for the primary and 275 km for the satellite, based on an assumed equal albedo of 0.135. Searches for moons In 2019, astronomers reported that observations by the Gemini North and Canada–France–Hawaii Telescope from 2013–2017 suggested the existence of a natural satellite or moon orbiting 2015 RR 245. The Gemini North and Hubble Space Telescope took further observations during 2019–2020 in an attempt at confirming 2015 RR 245's potential moon, but results have not yet been published 2026 y. References 30em 2017-11-22 last obs. JPL Small-Body Database Browser: 523794 (2015 RR245) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2523794 Jet Propulsion Laboratory 9 October 2018 523794 (2015 RR245) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=523794 12 December 2020 MPC/MPO/MPS Archive Minor Planet Center https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html 9 October 2018 How many dwarf planets are there in the outer solar system? (updates daily) California Institute of Technology Michael E. Brown 2013 https://web.gps.caltech.edu/~mbrown/dps.html 13 September 2019 List of Known Trans-Neptunian Objects Johnston's Archive 23 July 2023 https://www.johnstonsarchive.net/astro/tnoslist.html 31 July 2023 MPEC 2016-N67 : 2015 RR245 https://www.minorplanetcenter.net/mpec/K16/K16N67.html Tomatic A. U. Minor Planet Electronic Circular Minor Planet Center 10 July 2016 2016-N67 2016MPEC....N...67B New Dwarf Planet Discovered Far Beyond Pluto's Orbit space.com https://www.space.com/33387-dwarf-planet-discovery-2015-rr245.html 11 July 2016 Chang Kenneth Astronomers Discover New Likely Dwarf Planet, the Latest of Many https://www.nytimes.com/2016/07/14/science/astronomers-discover-new-likely-dwarf-planet.html 13 July 2016 The New York Times 14 July 2016 Distant Solar System Objects identified in the Pan-STARRS1 survey R.J. Weryk E. Lilly S. Chastel L. Denneau R. Jedicke E. Magnier R.J. Wainscoat K. Chambers H. Flewelling M.E. Huber C. Waters 17 July 2016 1607.04895 astro-ph.EP etal Michele T. Bannister Mike Alexandersen Susan D. Benecchi Ying-Tung Chen Audrey Delsanti Wesley C. Fraser December 2016 OSSOS. IV. Discovery of a Dwarf Planet Candidate in the 9:2 Resonance with Neptune The Astronomical Journal 152 6 8 2016AJ....152..212B 10.3847/0004-6256/152/6/212 1607.06970v2 55207350 free Confirmation of the discovery of a moon around 2015 RR245 https://www.gemini.edu/files/fast/df6ea262b6.pdf August 2019 Gemini Observatory 16 January 2020 dead https://web.archive.org/web/20190808195547/https://webcache.googleusercontent.com/search?q=cache%3AX05VeFygw-AJ%3Ahttps%3A%2F%2Fwww.gemini.edu%2Ffiles%2Ffast%2Fdf6ea262b6.pdf+&cd=24&hl=en&ct=clnk&gl=uk&lr=lang_en%7Clang_pl 8 August 2019 Orbital solutions for the OSSOS binaries https://meetingorganizer.copernicus.org/EPSC-DPS2019/EPSC-DPS2019-601-1.pdf Benoît Noyelles Daniel Hestroffer Jean-Marc Petit September 2019 EPSC-DPS Joint Meeting 2019 European Planetary Science Congress 13 2019EPSC...13..601N Confirming the binarity of Kuiper Belt Object 2015 RR245: a test of the streaming instability HST Proposal 16167 https://archive.stsci.edu/proposal_search.php?id=16167&mission=hst Wesley Fraser Mikulski Archive for Space Telescopes Space Telescope Science Institute 3 June 2020 Horizons Batch for 523794 (2015 RR245) on 2092-Aug-21 JPL Horizons Perihelion occurs when rdot flips from negative to positive https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27523794%27&START_TIME=%272092-Aug-01%27&STOP_TIME=%272092-Aug-31%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 2023-08-27 (JPL#21/Soln.date: 2023-Feb-09) External links MPEC 2016-N67 : 2015 RR245, Minor Planet Electronic Circular – Minor Planet Center New Dwarf Planet, Canada–France–Hawaii Telescope Kuiper Belt's Big, New, Far-Out Object, Sky & Telescope Outer Solar System Origins Survey (OSSOS) NyAN01UfcCw New Dwarf Planet Discovered Beyond Neptune (time 1:01 min.) Discovery announcement 2015RR245 523794 (523794) 2015 RR 245 523794 523794 523794 20150909