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Discovery[1]
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| Discovered by | M. E. Brown, C. A. Trujillo, D. L. Rabinowitz(?) |
| Discovery date | October 9, 2002 |
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Designations
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| MPC designation | (84522) 2002 TC302 |
| Alternate name(s) | none |
| Minor planet category |
TNO (SDO)[2] 5:2 resonance[3][4] |
| Epoch July 23, 2010 (JD 2455400.5) | |
| Aphelion | 10 752 Gm 71.870 AU (Q) |
| Perihelion | 5 864.1 Gm 39.199 AU (q) |
| Semi-major axis | 8 307.86 Gm 55.535 AU (a) |
| Eccentricity | 0.29415 |
| Orbital period | 151 162 d 413.86 yr |
| Average orbital speed | 3.93 km/s |
| Mean anomaly | 318.100° |
| Inclination | 34.976° |
| Longitude of ascending node | 23.823° |
| Argument of perihelion | 85.975° |
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Physical characteristics
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| Dimensions | 1150 ± 325 km[6] <1211 km[7] |
| Mass | ≈1.5×1021? kg[8] |
| Mean density | 2.0? g/cm3 |
| Equatorial surface gravity | 0.12–0.33? m/s2 |
| Escape velocity | 0.22–0.63? km/s |
| Sidereal rotation period |
? d |
| Albedo | 0.02–0.06[6] 0.051[7] |
| Spectral type | (red) B-V=1.03; V-R=0.67[9] |
| Apparent magnitude | 20.5 (opposition)[10] |
| Absolute magnitude (H) | 3.87±0.49[5] |
(84522) 2002 TC302 is a large, red 2:5 resonant[3] trans-Neptunian object discovered on October 9, 2002, by Mike Brown's team at the Palomar Observatory.[1] It is very likely a dwarf planet.
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2002 TC302 has an absolute magnitude (H) of 3.87,[5] and the Spitzer Space Telescope has estimated it to have a diameter of 1145.7±325 km.[6] This qualifies it as one of the largest dwarf-planet candidates. However, Brown notes that the measurement involves a very large potential error, and that the object is likely smaller, making its chances of being a dwarf planet "highly likely" rather than "virtually certain", as it would be if it were actually 1100 km in diameter.[11]
The red spectra suggests that 2002 TC302 has very little fresh ice on its surface and may explain why it has a lower-than-average estimated albedo of ~0.03. For example, (55565) 2002 AW197 has a higher estimated albedo (~0.12), resulting in a brighter absolute magnitude (H=3.3), and is estimated to be physically smaller (~730 km).[6]
2002 TC302 will come to perihelion in 2058.[5] Its perihelion (minimum distance from the Sun) of 39.1AU[5] is about the same as Pluto's semi-major axis (average distance from the Sun). It is classified as a scattered disc object.[2][3]
Given the long orbit that TNOs have around the Sun, 2002 TC302 comes to opposition in late October of each year at an apparent magnitude of 20.5.[10]
It has been observed 76 times over 9 years.[5]
Both the Minor Planet Center (MPC) and the Deep Ecliptic Survey (DES) show this dwarf-planet candidate to be in a 2:5 resonance with Neptune.[3][4] Due to the resonance, it completes 2 orbits for every 5 orbits of Neptune.
As of 2009, it is the largest dwarf-planet candidate that is known to be in a (non-plutino) resonance with Neptune. (Plutinos are objects in 2:3 mean motion resonance with Neptune. For every 2 orbits that a plutino makes, Neptune orbits 3 times.)
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A still frame showing the motion of 2002 TC302 relative to Neptune being held stationary |
The 2:5 resonance motion of 2002 TC302 (red) and the 2:3 resonance of Pluto (grey). Neptune is held stationary. |
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