2004 XR190
From Wikipedia, the free encyclopedia
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Discovery
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| Discovered by | Lynne Jones, Brett Gladman, John J. Kavelaars, Jean-Marc Petit, Joel Parker, Phil Nicholson |
| Discovery date | December 11, 2004 |
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Designations
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| MPC designation | 2004 XR190 |
| Alternate name | none |
| Minor planet category |
detached object |
| Epoch June 14, 2006 (JD 2453900.5) | |
| Aphelion | 9242.660 Gm (61.783 AU) |
| Perihelion | 7826.404 Gm (52.316 AU) |
| Semi-major axis | 8534.532 Gm (57.050 AU) |
| Eccentricity | 0.083 |
| Orbital period | 157390.985 d (430.91 a) |
| Average orbital speed | 3.94 km/s |
| Mean anomaly | 259.042° |
| Inclination | 46.746° |
| Longitude of ascending node | 252.369° |
| Argument of perihelion | 289.910° |
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Physical characteristics
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| Dimensions | 425–850 km (albedo 0.16-0.04)[1] 335–530 km (albedo 0.25-0.10)[2] |
| Mass | 0.6–4.8×1020 kg |
| Mean density | 1.5? g/cm³ |
| Equatorial surface gravity | 0.089–0.178 m/s² |
| Escape velocity | 0.195–0.389 km/s |
| Rotation period | ? |
| Albedo | <0.25? |
| Temperature | ~37–36 K |
| Spectral type | ? |
| Absolute magnitude | 4.47 |
2004 XR190 (also written 2004 XR190) is a trans-Neptunian object located in the scattered disc. Astronomers led by Lynne Jones of the University of British Columbia made the discovery as part of the Legacy Survey using the Canada-France-Hawaii Telescope (CFHT). The discovery team has temporarily nicknamed the object "Buffy", after the fictional vampire slayer, and proposed a different official name to the IAU.
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[edit] Orbit
Considered a detached object,[3][4] 2004 XR190 is particularly unusual for two reasons. With an inclination of 47 degrees, it is the most "tilted" object discovered thus far, traveling further "up and down" than "left to right" around the Sun when viewed edge-on along the ecliptic. Second, it has an unusually circular orbit for a scattered disc object. While it has been hypothesized that traditional Scattered Disc Objects (SDOs) 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 perihelions 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, rogue planets/planetary embryos in the early Kuiper belt, and resonance interaction with an outward migrating Neptune. The Kozai mechanism is capable of transferring the orbital eccentricity into an elevated inclination.[1]
Other than long-period comets and space probes,[5] Buffy is currently the third most distant known object in the solar system after Eris and Sedna.
 A side view of 2004 XR190's orbit, showing the object's high inclination. Units are AUs. |
[edit] Size
The object has a diameter estimated at around 500 kilometres, roughly a quarter the size of Pluto, and orbits between 52 and 62 AU (7.8 and 9.3 Tm) from the Sun.
[edit] References
- ^ a b R. L. Allen, B. Gladman (2006). "Discovery of a low-eccentricity, high-inclination Kuiper Belt object at 58 AU". The Astrophysical Journal 640. Discovery paper. Preprint
- ^ E. L. Schaller and M. E. Brown (2007). "Volatile loss and retention on Kuiper belt objects". Astrophysical Journal 659: I.61–I.64. doi:. Retrieved on 2008-04-02.
- ^ 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. ISBN 3540719571.
- ^ Lykawka, Patryk Sofia & Mukai, Tadashi. (2007). Dynamical classification of trans-neptunian objects: Probing their origin, evolution, and interrelation. Icarus Volume 189, Issue 1, July , Pages 213-232. doi:10.1016/j.icarus.2007.01.001.
- ^ Chris Peat. "Spacecraft escaping the Solar System". Heavens-Above. Retrieved on 2008-04-03.
[edit] External links
- MPEC circular detailing discovery
- Discovery webpage by research team
- Maggie McKee (2005-12-13). "Strange new object found at edge of Solar System", New Scientist.
- Canada-France-Hawaii Telescope Legacy Survey
- Orbital simulation from JPL (Java) / Ephemeris
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