(225088) 2007 OR10
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(225088) 2007 OR10
Artist's impression of (225088) 2007 OR10
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Discovery[1]
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| Discovered by | M. E. Schwamb M. E. Brown D. L. Rabinowitz Palomar Observatory (675) |
| Discovery date | 2007-07-17 announced: 2009-01-07 |
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Designations
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| MPC designation | (225088) 2007 OR10 |
| Minor planet category |
SDO[2] 10:3 resonance (DES)[3] |
| Epoch February 8, 2011 | |
| Aphelion | 100.79 AU (Q) 15.1 Tm |
| Perihelion | 33.62 AU (q) 5.03 Tm |
| Semi-major axis | 67.21 AU (a) 10.054 Tm |
| Eccentricity | 0.500 |
| Orbital period | 550.98 yr |
| Mean anomaly | 101.0° (M) |
| Inclination | 30.70° |
| Longitude of ascending node | 336.86° |
| Argument of perihelion | 207.18° |
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Physical characteristics
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| Dimensions | 1200+300 −200 km (fit to volatile-retention model)[5] 1280±210 km[6] |
| Albedo | ≈ that of Quaoar, 0.18 (assumed from spectrum)[5] 0.185+0.076 −0.052[6] |
| Spectral type | red[5] |
| Apparent magnitude | 21.3[7] |
| Absolute magnitude (H) | 2.0[4] |
(225088) 2007 OR10 is a very large trans-Neptunian object. It is the largest body in the Solar System without a name,[8] estimated to be between Haumea and Sedna in size. Its mass has never been measured, and its diameter is not well known. Some astronomers consider it a dwarf planet[9][10] and others consider it likely to be one,[11] but it has not been officially classified as a dwarf planet by the IAU.
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Contents
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Nickname
2007 OR10 was discovered by California Institute of Technology astronomers as part of the PhD thesis of Meg Schwamb, who was at the time a graduate student of Michael E. Brown.[12] Brown nicknamed the object "Snow White" for its presumed white color,[12] as it would have to be very large or very bright to be detected by their survey.[8] However, it turned out to be one of the reddest objects in the Kuiper belt, comparable only to Quaoar, so the nickname turned out to not be very appropriate. It was however also the "seventh dwarf" discovered by Brown's team, after Quaoar in 2002, Sedna in 2003, Haumea and Orcus in 2004, and Makemake and Eris in 2005.
2007 OR10 is currently the largest known object in the Solar System without an official name. In 2011 Brown decided he finally had enough information to justify giving it one,[5] since the discovery of water ice and the possibility of methane makes it noteworthy enough to warrant study.[12]
Distance
2007 OR10 came to perihelion around 1856.[4] It is currently 86.5 AU from the Sun.[7][13] This makes it the 3rd farthest known large body in the Solar System, after Eris (97 AU) and Sedna (87 AU).[8] It will be further from the Sun than Sedna in 2013.[13] 2007 OR10 will be further than both Sedna and Eris by 2045,[14] and it will reach aphelion (furthest distance from the Sun) in 2130.[13]
Absolute magnitude
The size of an object depends on its absolute magnitude (H) and the albedo (the amount of light it reflects). 2007 OR10 has an absolute magnitude (H) of 2.0 [4] This makes it the fifth brightest TNO known[15], a little less bright than Sedna (H=1.6; ≈1000 km)[16] and brighter than Orcus (H=2.3; ≈850 km).[17]
2007 OR10 is among the reddest objects known.[5] This is probably in part due to methane frosts, which turn red when bombarded by sunlight and cosmic rays.[5]
Surface composition and atmosphere
2007 OR10's spectrum shows signatures for both water ice and methane, which makes it similar in composition to Quaoar. The presence of red methane frost on the surfaces of both 2007 OR10 and Quaoar implies the existence of a tenuous methane atmosphere on both objects, slowly evaporating into space. Although 2007 OR10 comes closer to the Sun than Quaoar, and is thus warm enough that a methane atmosphere should evaporate, its larger mass makes retention of an atmosphere just possible.[5] The presence of water ice on the surface of 2007 OR10 implies a brief period of cryovolcanism in its distant past.[18]
Semi-major axis and orbital period
2007 OR10 is on an orbit similar to that of the dwarf planet Eris,[19] making it a scattered-disc object.[2] 2007 OR10 was discovered when searching for objects in the region of Sedna.[20]
2007 OR10 has been observed 46 times over seven oppositions with precovery images back to 1985.[4]
It was formally announced on January 7, 2009.[1]
 The orbit of 2007 OR10 compared to the orbit of Eris and Pluto. |
 The preliminary motion of 2007 OR10 librating in a 10:3 resonance with Neptune. This resonance is not confirmed and may be merely a near resonance.[3] |
The Deep Ecliptic Survey (DES) shows the nominal orbit as in a 10:3 resonance with Neptune.[3]
Dwarf-planet status
If a trans-Neptunian dwarf-planet candidate does not have a known natural satellite with a well determined orbit, astronomers can not directly calculate the objects mass (see three-body problem) to determine if it might be in hydrostatic equilibrium. 2007 OR10 has no known satellite, so its mass is unknown.
Most objects at that distance are too small and too far away to directly resolve their diameters. Thus candidates' diameters can generally only be estimated from their absolute magnitude and best-fit albedo estimates. Mike Brown's diameter range of 2007 OR10 is based on an assumed albedo that is a best-fit from his model[5], and this agrees with measurements derived from observations from the Herschel space observatory.[6] It is accepted as a dwarf planet by Mike Brown,[citation needed] and is listed on his website as "nearly certainly" a dwarf planet, saying it "must be a dwarf planet even if predominantly rocky".[9] Scott Sheppard et al. (2011) believe it is "likely" to be a dwarf planet.[11]
References
- ^ a b "MPEC 2009-A42 : 2007 OR10". Minor Planet Center. 2009-01-07. http://minorplanetcenter.org/mpec/K09/K09A42.html. Retrieved 2009-01-20.
- ^ a b "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. http://www.minorplanetcenter.org/iau/lists/Centaurs.html. Retrieved 2009-01-20.
- ^ a b c Marc W. Buie (2008-08-23). "Orbit Fit and Astrometric record for 225088". SwRI (Space Science Department). http://www.boulder.swri.edu/~buie/kbo/astrom/225088.html. Retrieved 2009-03-11.
- ^ a b c d e "JPL Small-Body Database Browser: 225088 (2007 OR10)". 2009-11-06 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007OR10. Retrieved 2011-01-02.
- ^ a b c d e f g h Michael E. Brown; Burgasser, A.J.; Fraser W.C. (2011). "The Surface Composition of Large Kuiper Belt Object 2007 OR10". Mike Brown's Website. arXiv:1108.1418. http://www.gps.caltech.edu/~mbrown/papers/ps/or10.pdf. Retrieved 2011-08-08.
- ^ a b c Santos-Sanz, P., Lellouch, E., Fornasier, S., Kiss, C., Pal, A., Müller, T. G., Vilenius, E., Stansberry, J., Mommert, M., Delsanti, A., Mueller, M., Peixinho, N., Henry, F., Ortiz, J. L., Thirouin, A., Protopapa, S., Duffard, R., Szalai, N., Lim, T., Ejeta, C., Hartogh, P., Harris, A. W., & Rengel, M. (2012). “TNOs are Cool”: A Survey of the Transneptunian Region IV - Size/albedo characterization of 15 scattered disk and detached objects observed with Herschel Space Observatory-PACS
- ^ a b "AstDys 2007OR10 Ephemerides". Department of Mathematics, University of Pisa, Italy. Archived from the original on 2009-05-17. http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.3.0&n=2007OR10. Retrieved 2009-03-16.
- ^ a b c Michael E. Brown (2009-03-10). "Snow White needs a bailout". Mike Brown's Planets (blog). Archived from the original on 2009-05-17. http://www.mikebrownsplanets.com/2009/03/snow-white-needs-bailout.html. Retrieved 2010-02-17.
- ^ a b Michael E. Brown. "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. http://www.gps.caltech.edu/~mbrown/dps.html. Retrieved 2011-09-23.
- ^ "Ice & Maybe Methane on 'Snow White' Dwarf Planet". W. M. Keck Observatory. 2011-08-22. http://www.keckobservatory.org/news/snow_white_dwarf/. Retrieved 2012-01-05.
- ^ a b Sheppard, Scott S.; Trujillo, C.; Udalski, A,; et al. (2011). "A Southern Sky and Galactic Plane Survey for Bright Kuiper Belt Objects". Astronomical Journal 142 (4). arXiv:1107.5309. Bibcode 2011AJ....142...98S. doi:10.1088/0004-6256/142/4/98.
- ^ a b c "Astronomers Find Ice and Possibly Methane On Snow White, a Distant Dwarf Planet". Science Daily. August 22, 2011. http://www.sciencedaily.com/releases/2011/08/110822124955.htm. Retrieved 2011-08-22.
- ^ a b c "Horizon Online Ephemeris System". California Institute of Technology, Jet Propulsion Laboratory. http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=2007OR10. Retrieved 2012-01-31.
- ^ JPL Horizons On-Line Ephemeris System (2011-02-17). "Horizons Output for Sedna 2076/2114". http://home.surewest.net/kheider/astro/Sedna2076.txt. Retrieved 2011-02-17.
- ^ Mike Brown (2011). "The Redemption of Snow White (Part 2 of 3)". Mike Brown's Planets. http://www.mikebrownsplanets.com/2011/08/redemption-of-snow-white-part-2.html. Retrieved 2012-02-08.
- ^ "JPL Small-Body Database Browser: 90377 Sedna (2003 VB12)". 2008-10-23 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Sedna. Retrieved 2009-01-21.
- ^ "JPL Small-Body Database Browser: 90482 Orcus (2004 DW)". 2008-12-04 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Orcus. Retrieved 2009-02-05.
- ^ Mike Brown (2011). "The Redemption of Snow White (Part 3 of 3)". Mike Brown's Planets. http://www.mikebrownsplanets.com/2011/08/redemption-of-snow-white-part-3-of-3.html#more. Retrieved 2011-08-23.
- ^ "JPL Small-Body Database Browser: 136199 Eris (2003 UB313)". 2008-10-04 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Eris. Retrieved 2009-01-21.
- ^ Schwamb, Megan E.; Michael E. Brown, David L. Rabinowitz (2009). "A Search for Distant Solar System Bodies in the Region of Sedna". Astrophysical Journal Letters. arXiv:0901.4173. Bibcode 2009ApJ...694L..45S. doi:10.1088/0004-637X/694/1/L45.
External links
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Wikimedia Commons has media related to: (225088) 2007 OR10 |
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- 2007 OR10 Precovery Images
- 2007 OR10 Minor planet designation number
- The redemption of Snow White (Part 1) (Mike Brown blog 9 Aug 2011)
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