(278361) 2007 JJ43

Classical Kuiper belt object yes Image of 2007 JJ 43 from the Keck Observatory, slight elongation is probably due to atmospheric distortion. possible dwarf planet Palomar Obs. Palomar Obs. 14 May 2007 (278361) 2007 JJ 43 2007 JJ43.png yes TNOScatNear2:1 resonance with Neptune4 (barycentric)barycentric These orbital elements are expressed in terms of the Solar System Barycenter (SSB) as the frame of reference. Due to planetary perturbations, the Sun revolves around the SSB at non-negligible distances, so heliocentric-frame orbital elements and distances (such as those given in JPL's Small-Body Database) can vary on short timescales. 27 August 2011 (JD 2455800.5) 2 7647 days (20.94 yr) 10 May 2002 (NEAT) 48.3245 AU 40.3911 AU ≈ 2 April 2037±6 days 56.2579 AU 0.16417 335.94 a (120801 d) 12.0393° 272.55° 6.454° 340.04° 0 530 km(assuming albedo at 0.08) 598 km(assuming albedo at 0.079)610 +170 -140 km (2015)504 105 km (2021)57 0.13 0.09 0.07 (Cluster average albedo, 2015)40.11 0.09 (Median albedo, 2021)55, 57 B-V 1.020 0.028V-R 0.590 0.020R-I 0.500 0.020g'-r' 0.77 0.03g'-i' 1.12 0.04r'-i' 0.35 0.04BR 12.097 h6.04 h4.83 h209.66 h20 20.820.35 0.265 (R-band) 3.2 (R-band)4.493.9 (Hv)44.50 0.45 (Hv) (278361) 2007 JJ 43 is a large trans-Neptunian object (TNO) orbiting the Sun near the outer edge of the Kuiper belt. Its discovery images were taken in 2007, and its absolute magnitude of 4.5 is one of the twenty brightest exhibited by unnamed TNOs.September 2026 It has a diameter of roughly 504 to 610 km,57 making it a possible dwarf planet. History Discovery June 2026 thumb|right|The 1.2-meter Samuel Oschin telescope that was used to discover 2007 JJ 43 at Palomar Observatory on 14 May 2007 2007 JJ 43 was discovered by the Palomar Mountain telescope with Megan Schwamb, Michael E. Brown, and David L. Rabinowitz on 14 May 2007, using discovery images taken by the 1.2-meter Samuel Oschin telescope at the Palomar Observatory in California. Its discovery was also a part of the Palomar Distant Solar System Survey, the survey aimed to find objects in the region around Sedna, farther than 50 AU from the Sun. The survey was designed to detect the orbital movements of distant objects that were at least 1,000 AU from the Sun. Its discovery was further announced on 5 July 2007. The object has precovery images back to 10 May 2002 by Palomar Mountain (NEAT). Further observations The observation arc of 2007 JJ 43 begins with an observation on 10 May 2002 by Palomar Mountain (NEAT). Following this, 2007 JJ 43 has been observed by various telescopes, including the Las Campanas Observatory, European Southern Observatory, and Palomar Mountain. As of September 2026, 209 observations of this object had been recorded for over a period of 20.94 years. Provisional designation and numbering The object was officially given the provisional designation of 2007 JJ 43 by the Minor Planet Center on 5 July 2007. The provisional designation of 2007 JJ 43 indicates its discovery date, the first letter represents the first half of May and the second letter and numbers (43) mean that it is the 1085th object discovered during that half-month.The second letter 'J' indicates that it is the 10th object discovered on the 44th cycle of discoveries. Each completed cycle consists of 25 letters representing discoveries, hence 10 + (43 completed cycles × 25 letters) 1085. 2007 JJ 43 was the minor planet number 278361 by the IAU. As of 2026, 2007 JJ 43 has not been officially given any name by the International Astronomical Union. Orbit and classification Orbital characteristics 2007 JJ 43 orbits the Sun at a distance of 40.4–56.3 AU with an semi-major axis or average orbital distance of 48.3 AU once every 335.9 yearsbarycentric (for reference, Neptune's orbit is at 30 AU). Its orbit has a relatively high eccentricity of 0.164 and an inclination of 12.04° with respect to the ecliptic.barycentric 2026, it is about 40.5 AU from the Sun. Classification June 2026 2007 JJ 43 is located in the classical region of the Kuiper belt 39–48 AU from the Sun, and is thus classified as a typical member of a classical Kuiper belt object (also known as a "cubewano"). This classical population is mostly concentrated in a range between 42 and 47 AU. The high orbital inclination of 2007 JJ 43 makes it a dynamically "hot" member of the classical Kuiper belt, separating it from the "cold" classical Kuiper Belt objects that have inclinations under 5°. The hot classical Kuiper belt objects are believed to have been scattered by the gravitational influence of Neptune into their dynamically excited orbital paths during the Solar System's early history.230 However, a 2015 study found that 2007 JJ 43 is likely in a 2:1 resonance with Neptune. Physical characteristics Size, mass, and density thumb|right|180px|2007 JJ 43 compared to the asteroid 4 Vesta, with their size and true color. Assuming it has a typical cluster average geometric albedo, this would make it roughly the same size as Ixion (about 697 km diameter). In a 2015 paper in the Astrophysical Journal Letters, András Pál and colleagues estimate a diameter of 2007 JJ 43 of 610 +170 -140 km. A following study in 2021 further refined its diameter down to 504 105 km,57 assuming a median geometric albedo,55 making it very similar in size to Saturn's moon Enceladus (504.2 km in diameter). 2007 JJ 43 is not known to have any natural satellites or moons, which means there is currently no way to measure its mass and density,1,3 thus, its mass and density are unknown as of 2026. The large size of it makes it a possible dwarf planet. However, based on its size of 610 +170 -140 km or 504 105 km,57 it belongs to the class of "mid-sized" TNOs between 400 and 1000 km mi in diameter which scientists proposed in 2019. These mid-sized TNOs are believed to represent the transition between small, low-density TNOs and large, high-density dwarf planets.1 Planetary scientists have hypothesized that mid-sized TNOs in the lower range of 400–1000 km may have highly porous and unheated interiors, because TNOs in the lower range of this zone (such as Uni and Gǃkúnǁʼhòmdímà) have been found to have low densities around 1 g/cm3. Surface and spectra Composition and spectrum A paper released on 28 June 2015 by Gourgeot et al. using the instrument X-Shooter at the Paranal Observatory, covering 300 to 2480 nm shows that 2007 JJ 43‘s spectra is mostly flat. and can be considered to be a blue-red object. They detected no absorption bands of icy elements, and their models show crystalline water ice is likely does not have a high concentration on the surface of 2007 JJ 43, with no more than a concentration of 6.5%. They also proposed a surface composition of 50% complex organics. Observations covering about one-third of the entire surface of 2007 JJ 43 show no differences, showing its surface is mostly homogeneous. A following 2021 study measured a surface composition of 40 30 % H2O (water), 40 20 % silicates, and 20 10 % organics. Color and albedo 2007 JJ 43 has color indices of: B-V of 1.020 0.028, V-R of 0.590 0.020, and R-I of 0.500 0.020. A later study led by Susan D. Benecchi and Scott S. Sheppard shows that it has color indices of: g'-r' of 0.77 0.03, g'-i' of 1.12 0.04, and r'-i' of 0.35 0.04. A earlier paper by only Scott S. Sheppard in 2010, shows that 2007 JJ 43 has color indices of: g-r of 0.81 0.02, a g-i of 1.11 0.02, a r-i of 0.29 0.02, a B-R of 1.61 0.02, a V-R of 0.59 0.02, a R-I of 0.50 0.02, and a B-I of 2.12 0.02. András Pál and colleagues assumed a cluster average geometric albedo of 0.13 0.09 0.07 for 2007 JJ 43. A 2021 study by Fernández Valenzuela refined its albedo to 0.11 0.09 by assuming the median albedos of their samples.55, 57 Rotation 2007 JJ 43 rotates on its axis once every 12.1 hours, with a light curve amplitude of approximately 0.10, indicating an approximate spheroidal shape. Lack of moons Observations by Mike Brown in 2012, using the W. M. Keck Observatory, suggest that 2007 JJ 43 does not have a significantly sized companion. See also List of Solar System objects by size List of trans-Neptunian objects List of minor planets: 278001–279000 Notes References 30em 278361 (2007 JJ43) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=278361 14 May 2002 Gourgeot F. Barucci M. A. Alvarez-Candal A. Merlin F. Perna D. Lazzaro D. 2015-09-29 TNO (278361) 2007 JJ43observed with X-Shooter https://www.aanda.org/articles/aa/full_html/2015/10/aa26014-15/aa26014-15.html Astronomy & Astrophysics 582 A13 10.1051/0004-6361/201526014 free 2015A&A...582A..13G 0004-6361 Sheppard Scott S. 4 March 2010 The Colors of Extreme Outer Solar System Objects The Astronomical Journal 139 4 1394–1405 10.1088/0004-6256/139/4/1394 free 1001.3674 2010AJ....139.1394S JPL Horizons Observer Location: @sun (Perihelion occurs when deldot changes from negative to positive. Uncertainty in time of perihelion is 3-sigma.) JPL Small-Body Database Browser: 2007 JJ43 Retrieved: 2011-06-18 AstDys 2007 JJ43 Summary Retrieved: 2012-02-03 18 August 2020 List of Known Trans-Neptunian Objects Johnston's Archive Wm. Robert Johnston http://www.johnstonsarchive.net/astro/tnoslist.html 23 July 2021 AstDys 2007 JJ43 Ephemerides Department of Mathematics, University of Pisa, Italy https://newton.spacedys.com/astdys/index.php?pc=1.1.3.0&n=2007JJ43 2012-02-03 Pushing the Limits: K2 Observations of the Trans-Neptunian Objects 2002 GV31 and (278361) 2007 JJ43 Pál A. Szabó R. Szabó Gy. M. Kiss L. L. Molnár L. Sárneczky K. Kiss Cs. 1 The Astrophysical Journal Letters 804 2 L45 2015 1504.03671 2015ApJ...804L..45P 10.1088/2041-8205/804/2/L45 117489359 Marc W. Buie Marc W. Buie Orbit Fit and Astrometric record for 278361 SwRI (Space Science Department) http://www.boulder.swri.edu/~buie/kbo/astrom/278361.html 2018-02-18 How many dwarf planets are there in the outer solar system? (updates daily) California Institute of Technology Michael E. Brown Michael E. Brown 2013 http://web.gps.caltech.edu/~mbrown/dps.html 2019-08-13 live https://web.archive.org/web/20190531134353/http://web.gps.caltech.edu/~mbrown/dps.html 2019-05-31 2007 JJ43 doesn't have a big moon. There could be a small one hiding in there 2012-02-03 Twitter Plutokiller https://twitter.com/#!/plutokiller/status/165453799052423168 2012-02-03 (moonless) Scott Sheppard Yanga Fernandez Arielle Moullet The Albedos, Sizes, Colors and Satellites of Dwarf Planets Compared with Newly Measured Dwarf Planet 2013 FY27 The Astronomical Journal 156 6 270 6 September 2018 1809.02184 10.3847/1538-3881/aae92a 2018AJ....156..270S 119522310 free W. M. Grundy K. S. Noll M. W. Buie S. D. Benecchi D. Ragozzine H. G. Roe The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK 126) http://www2.lowell.edu/users/grundy/abstracts/preprints/2019.G-G.pdf Icarus December 2019 334 30–38 10.1016/j.icarus.2018.12.037 2019Icar..334...30G 126574999 2019-04-07 2026-03-30 https://web.archive.org/web/20190407045339/http://www2.lowell.edu/~grundy/abstracts/preprints/2019.G-G.pdf dead etal W. M. Grundy W. B. McKinnon E. Ammannito M. Aung J. Bellerose F. Brenker Exploration Strategy for the Ice Dwarf Planets 2013-2022 https://www.lpi.usra.edu/decadal/sbag/community_wp/SB_Community_WP_Final_Dwarfs.pdf American Geophysical Union Fall Meeting 2009 December 2009 P43D-1471 2009AGUFM.P43D1471G dead https://web.archive.org/web/20250330030249/https://www.lpi.usra.edu/decadal/sbag/community_wp/SB_Community_WP_Final_Dwarfs.pdf 2025-03-30 Donald K. Yeomans https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%278%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%272000-01-01%27&STOP_TIME=%272000-01-02%27&STEP_SIZE=%27200%20years%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%27 HORIZONS Web-Interface for Neptune Barycenter (Major Body=8) JPL Horizons On-Line Ephemeris System 18 July 2014 7 September 2021 https://web.archive.org/web/20210907055935/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%278%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%272000-01-01%27&STOP_TIME=%272000-01-02%27&STEP_SIZE=%27200%20years%27&CENTER=%27%400%27&OUT_UNITS=%27AU-D%27 live —Select "Ephemeris Type: Orbital Elements", "Time Span: 2000-01-01 12:00 to 2000-01-02". ("Target Body: Neptune Barycenter" and "Center: Solar System Barycenter (@0)".) Sheppard Scott S. Udalski Andrzej Trujillo Chadwick Kubiak Marcin Pietrzynski Grzegorz Poleski Radoslaw Soszynski Igor Szymański Michal K. Ulaczyk Krzysztof A Southern Sky and Galactic Plane Survey for Bright Kuiper Belt Objects The Astronomical Journal 2011 142 4 98 10.1088/0004-6256/142/4/98 1107.5309 2011AJ....142...98S Malhotra Renu Resonant Kuiper belt objects: a review Geoscience Letters 6 1 2019 2196-4092 32215241 7067275 10.1186/s40562-019-0142-2 free 12 1911.07897 2019GSL.....6...12M Patryk Sofia Lykawka Mukai Tadashi Dynamical classification of trans-neptunian objects: Probing their origin, evolution, and interrelation Icarus July 2007 189 1 213–232 10.1016/j.icarus.2007.01.001 2007Icar..189..213L 122671996 Susan D. Benecchi Scott Sander Sheppard Light Curves of 32 Large Transneptunian Objects The Astronomical Journal 25 March 2013 145 5 124 10.1088/0004-6256/145/5/124 1301.5791 2013AJ....145..124B JPL/HORIZONS (278361) 2007 JJ43 (Barycentric) https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27278361%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%27JD2461000.5%27&STOP_TIME=%27JD2461001.5%27&STEP_SIZE=%271y%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%27 JPL Horizons On-Line Ephemeris System Jet Propulsion Laboratory 2026-09-08 Solution using the Solar System Barycenter. Ephemeris Type: Elements and Center: @0) JPL/HORIZONS (278361) 2007 JJ43 (Heliocentric) https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND='278361'&TABLE_TYPE='ELEMENTS'&START_TIME='JD2460800.5'&STOP_TIME='JD2461000.5'&STEP_SIZE='200d'&CENTER='500@10'&OUT_UNITS='AU-D' JPL Horizons On-Line Ephemeris System Jet Propulsion Laboratory 2026-09-08 Solution using the Sun. Ephemeris Type: Elements and Center: @sun) Gray Bill MPECs for 2007 Project Pluto https://www.projectpluto.com/mpecs/2007.htm az 2026-09-14 How Are Minor Planets Named? https://www.minorplanetcenter.net/iau/info/HowNamed.html Minor Planet Center 2026-09-14 MPC MPC/MPO/MPS Archive IAU https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html 2026-09-14 en Hainaut O. R. Boehnhardt H. Protopapa S. Colours of minor bodies in the outer solar system https://www.aanda.org/articles/aa/full_html/2012/10/aa19566-12/aa19566-12.html Astronomy & Astrophysics en 546 A115 10.1051/0004-6361/201219566 free 0004-6361 https://web.archive.org/web/20260214004001/https://www.aanda.org/articles/aa/full_html/2012/10/aa19566-12/aa19566-12.html 2026-02-14 October 2012 Ayala-Loera C Alvarez-Candal A Ortiz J L Duffard R Fernández-Valenzuela E Santos-Sanz P Morales N Absolute colours and phase coefficients of trans-Neptunian objects: HV − HR and relative phase coefficients Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 481 2 2018-08-31 0035-8711 10.1093/mnras/sty2363 free 1848–1857 1808.09938 Fernández-Valenzuela E. Pinilla-Alonso N. Stansberry J. Emery J. P. Perkins W. Van Laerhoven C. Gladman B. J. Fraser W. Cruikshank D. Lellouch E. Müller T. G. Grundy W. M. Trilling D. Fernandez Y. Dalle Ore C. Compositional Study of Trans-Neptunian Objects at λ > 2.2 μm The Planetary Science Journal American Astronomical Society 2 1 2021-01-25 2632-3338 10.3847/psj/abc34e free 10 2011.07121 2021PSJ.....2...10F Kilic Y. Braga-Ribas F. Pereira C. L. Ortiz J. L. Sicardy B. Santos-Sanz P. Erece O. Rizos J. L. Gómez-Limón J. M. Margoti G. Souami D. Morgado B. Gomes-Junior A. Catani L. M. Desmars J. Kretlow M. Rommel F. Duffard R. Alvarez-Candal A. Camargo J. I. B. Kaplan M. Morales N. Herald D. Assafin M. Benedetti-Rossi G. Sfair R. Savalle R. Arcas-Silva J. Bernasconi L. Blank T. 1 Constraining the size, shape, and albedo of the large trans-Neptunian object (28978) Ixion with multi-chord stellar occultations Astronomy & Astrophysics 2026 707 A70 10.1051/0004-6361/202557970 free 2026A&A...707A..70K 2601.09639 Jacobson Robert. A. The Orbits of the Main Saturnian Satellites, the Saturnian System Gravity Field, and the Orientation of Saturn's Pole The Astronomical Journal November 1, 2022 164 5 199 10.3847/1538-3881/ac90c9 free 2022AJ....164..199J 252992162 MPEC 2008-E110: 2007 JJ43 IAU Minor Planet Center https://www.minorplanetcenter.net/mpec/K08/K08EB0.html 2026-09-28 M. E. Schwamb Megan Schwamb M. E. Brown Michael E. Brown D. L. Rabinowitz David L. Rabinowitz D. Ragozzine 25 August 2010 Properties of the Distant Kuiper Belt: Results from the Palomar Distant Solar System Survey The Astrophysical Journal Letters 720 2 1691–1707 10.1088/0004-637X/720/2/1691 1007.2954 2010ApJ...720.1691S 5853566 MPEC 2007-N14 : 2007 JF43, 2007 JH43, 2007 JJ43, 2007 JK43 IAU Minor Planet Center https://www.minorplanetcenter.net/mpec/K07/K07N14.html 2026-09-29 External links List of Transneptunian Objects, Minor Planet Center 278361 (268361) 2007 JJ 43 Category:Classical Kuiper belt objects Category:Discoveries by the Palomar Observatory Category:Possible dwarf planets 20070514