(612911) 2004 XR190

Minor planet in the scattered disc December 2018 yes (612911) 2004 XR 190 #C2E0FF 2004-xr190_hst.jpg Hubble Space Telescope image of 2004 XR 190, taken in October 2010 CFEPS Maunakea Obs. 11 December 2004 (612911) 2004 XR 190 "Buffy" (nickname) TNO detached SDO distant 2025 Ṃay 05 (JD 2460800.5) 2 20.00 yr (8,036 d) 6 December 2002 64.05 AU 51.59 AU 26 May 2114±5 days 57.82 AU 0.1077 439.7 yr (160,600 d) 287.1° 0.00224 ms / day 46.5065° 252.313° 280.5° 0 335 - 530 km 425 - 850 km 350 - 784 kmUsing AstDyS magnitude, Bruton formula, and commonly assumed minor planet albedo range of 0.05 to 0.25 (as detailed by Bruton) 560+ kmeuraster.net - 2021 European Asteroidal Occultation Results https://euraster.ericfrappa.com/results/2021/index.html#0122-- euraster.ericfrappa.com 2 February 2026 600 170 km 0.04–0.16 0.09 (assumed) 0.095 0.23 (R-band) 0.10–0.25 21.8 0.2 (r-band) 21.9 0.8 -1.5 (G-band) 21.85 0.35 (wide-band) 21.8 0.7 0.4 (several other bands) 3.802 0.022 (R-band) 4.3 4.4 4.47Reverse derived using Allen diameter and albedo data, and Bruton formula 4.50Reverse derived using Schaller diameter and albedo data, and Bruton formula (612911) 2004 XR 190, internally nicknamed Buffy by the discovery team, is a trans-Neptunian object, classified as both a scattered disc object and a detached object, located in the outermost region of the Solar System. It was first observed on 11 December 2004, by astronomers with the Canada–France Ecliptic Plane Survey at the Mauna Kea Observatories, Hawaii, United States. 2004 XR 190 is one of the largest known highly inclined (> 45°) objects. With a perihelion of 51 AU, it belongs to a small and poorly understood group of very distant objects with moderate eccentricities. Discovery and naming 2004 XR 190 was discovered on 11 December 2004. It was discovered by astronomers led by (Rhiannon) Lynne Allen of the University of British Columbia as part of the Canada–France Ecliptic Plane Survey (CFEPS) using the Canada–France–Hawaii Telescope (CFHT) near the ecliptic. The team included Brett Gladman, John Kavelaars, Jean-Marc Petit, Joel Parker and Phil Nicholson. In 2015, six precovery images from 2002 and 2003 were found in Sloan Digital Sky Survey data. The object was nicknamed "Buffy" by the discovery team, after the fictional vampire slayer Buffy Summers, and the team proposed several Inuit-based official names to the International Astronomical Union in 2005. Orbit and classification thumb|left|2004 XR 190 is located in the "gap", a poorly understood region. 2004 XR 190 orbits the Sun at a distance of 51.1–63.4 AU once every 433 years and 3 months (158,242 days; semi-major axis of 57.26 AU). Its orbit has a moderate eccentricity of 0.11 and a high inclination of 47° with respect to the ecliptic. It came to aphelion around 1901. It belongs to the same group as 2014 FC 72, 2014 FZ 71, 2015 FJ 345 and 2015 KQ 174 (also see diagram), that are poorly understood for their large perihelia combined with moderate eccentricities. Considered a scattered and detached object, 2004 XR 190 is particularly unusual as it has an unusually circular orbit for a scattered-disc object (SDO). Although it is thought that traditional scattered-disc objects have been ejected into their current orbits by gravitational interactions with Neptune, the low eccentricity of its orbit and the distance of its perihelion (SDOs generally have highly eccentric orbits and perihelia less than 38 AU) seems hard to reconcile with such celestial mechanics. This has led to some uncertainty as to the current theoretical understanding of the outer Solar System. The theories include close stellar passages, unseen planet/rogue planets/planetary embryos in the early Kuiper belt, and resonance interaction with an outward-migrating Neptune. The Kozai mechanism is capable of transferring orbital eccentricity to a higher inclination. The object is one of the largest objects with an inclination larger than 45°, traveling further "up and down" than "left to right" around the Sun when viewed edge-on along the ecliptic. Physical characteristics With assumed albedos between 0.04 and 0.25, and absolute magnitudes from 4.3 to 4.6, 2004 XR 190 has an estimated diameter of 335 to 850 kilometers; the mean arrived at by considering the two single-figure estimates plus the centre points of the three ranges is 562 km, approximately a quarter the diameter of Pluto. As of 2018, no well-documented spectral type and color indices, nor a rotational lightcurve have been obtained from spectroscopic and photometric observations; however, Johnston's Archive lists a "taxonomic type" of "BR", and a "B-R magnitude" of 1.24. The rotation period, pole and shape officially remain unknown. Gallery Notes References 30em 2024-12-06 last obs. JPL Small-Body Database Browser: (2004 XR190) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3308265 Jet Propulsion Laboratory 2025-08-18 2004 XR190 Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=2004+XR190 13 December 2018 MPEC 2005-X72 : 2004 XR190 IAU Minor Planet Center 12 December 2005 https://www.minorplanetcenter.net/iau/mpec/K05/K05X72.html 13 December 2018 (K04XJ0R) 2004 XR190 AstDyS-2, Asteroids Dynamic Site https://newton.spacedys.com/astdys/index.php?pc=1.1.0&n=2004+xr190 18 August 2019 List of Known Trans-Neptunian Objects Johnston's Archive 7 October 2018 Johnston Wm. Robert http://www.johnstonsarchive.net/astro/tnoslist.html 13 December 2018 Jewitt, David, Morbidelli, Alessandro, & Rauer, Heike. (2007). Trans-Neptunian Objects and Comets: Saas-Fee Advanced Course 35. Swiss Society for Astrophysics and Astronomy. Berlin: Springer. 3-540-71957-1. Patryk Sofia Lykawka Tadashi Mukai July 2007 Dynamical classification of trans-neptunian objects: Probing their origin, evolution, and interrelation Icarus 189 1 213–232 2007Icar..189..213L 10.1016/j.icarus.2007.01.001 R. L. Allen B. Gladman J. J. Kavelaars J.-M. Petit J. W. Parker P. Nicholson March 2006 Discovery of a Low-Eccentricity, High-Inclination Kuiper Belt Object at 58 AU The Astrophysical Journal 640 1 L83–L86 2006ApJ...640L..83A 10.1086/503098 astro-ph/0512430 15588453 (Discovery paper) E. L. Schaller M. E. Brown April 2007 Volatile Loss and Retention on Kuiper Belt Objects http://www.gps.caltech.edu/~mbrown/papers/ps/volatiles.pdf The Astrophysical Journal 659 1 I.61–I.64 2007ApJ...659L..61S 10.1086/516709 10782167 13 December 2018 Strange new object found at edge of Solar System New Scientist Maggie McKee https://www.newscientist.com/article/dn8455 13 December 2018 http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=2004XR190 Horizon Online Ephemeris System California Institute of Technology, Jet Propulsion Laboratory 2009-03-23 JPL Small-Body Database Search Engine: H < 6.5 (mag) JPL Solar System Dynamics http://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=all;obj_numbered=all;OBJ_field=0;ORB_field=0;c1_group=OBJ;c1_item=Ai;c1_op=%3C;c1_value=6.5;table_format=HTML;max_rows=100;format_option=comp;c_fields=AcBhBgBjBiBnBsCjCpAi;.cgifields=format_option;.cgifields=ast_orbit_class;.cgifields=table_format;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=com_orbit_class&query=1&c_sort=BjD 2014-03-27 Dan Bruton Conversion of Absolute Magnitude to Diameter for Minor Planets http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html Stephen F. Austin State University, College of Sciences and Mathematics, Department of Physics, Engineering and Astronomy 15 August 2019 https://web.archive.org/web/20110723191750/http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html 23 July 2011 Rommel Flavia Luane 2022-12-19 DETERMINATION OF PHYSICAL PROPERTIES AND TOPOGRAPHY OF TNOS FROM STELLAR OCCULTATIONS AND ROTATIONAL LIGHT CURVES: THE CASE OF 2002 MS4 OBJECT http://sistede.on.br:8080/handle/tede/149 PhD Rio de Janeiro Observatório Nacional 26 September 2025 External links MPEC 2005-X72 : 2004 XR190, Minor Planet Electronic Circular, detailing discovery Discovery webpage by research team Canada-France-Hawaii Telescope Legacy Survey List Of Centaurs and Scattered-Disk Objects, Minor Planet Center 2004XR190 3308265 612911 (612911) 2004 XR 190 612911 612911 20041211