(55637) 2002 UX25

(55637) 2002 UX25
2002 UX25 and satellite, as seen by Hubble
Discovery[1]
Discovered bySpacewatch (291)
Discovery siteKitt Peak National Obs.
Discovery date30 October 2002
Designations
(55637) 2002 UX25
Cubewano (MPC)[2]
Extended (DES)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 2
Observation arc25.26 yr (9,228 days)
Earliest precovery date12 October 1991
Aphelion48.491 AU
Perihelion36.485 AU
42.488 AU
Eccentricity0.1413
276.95 yr (101,157 days)
4.54 km/s
295.71°
0° 0m 12.96s / day
Inclination19.484°
204.68°
≈ 5 September 2066[4]
±3 days
279.00°
Known satellites1
(ø: 190–260 km)[5][6]
Physical characteristics
665±29 km[7]
659±38 km[8]
Mass(1.25±0.03)×1020 kg[6]
Mean density
0.82±0.11 g/cm3
(assuming equal densities
for primary and satellite)[6]
0.80±0.13 g/cm3[8]
Equatorial surface gravity
0.075 m/s2
Equatorial escape velocity
0.227 km/s
14.382±0.001 h[9]
0.107+0.005
−0.008[7]
0.1±0.01[8]
Temperature≈ 43 K
B–V=1.007±0.043[10]
V−R=0.540±0.030[10]
V−I=1.046±0.034[10]
19.8 [11]
3.87±0.02,[9] 4.0[1]

(55637) 2002 UX25 (provisional designation 2002 UX25) is a trans-Neptunian object that orbits the Sun in the Kuiper belt beyond Neptune. It briefly garnered scientific attention when it was found to have an unexpectedly low density of about 0.82 g/cm3.[12] It was discovered on 30 October 2002, by the Spacewatch program;[13] as of August 2024, the object has yet to be named.

2002 UX25 has an absolute magnitude of about 4.0,[1] and Spitzer Space Telescope results estimate it to be about 681 km in diameter.[14] The low density of this and many other mid sized TNOs implies that they have likely never compressed into fully solid bodies, let alone differentiated or collapsed into hydrostatic equilibrium, and so are highly unlikely to be dwarf planets.[15]

  1. ^ a b c d Cite error: The named reference jpldata was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference MPEC 2009-C70 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Buie was invoked but never defined (see the help page).
  4. ^ JPL Horizons Observer Location: @sun (Perihelion occurs when deldot changes from negative to positive. Uncertainty in time of perihelion is 3-sigma.)
  5. ^ Cite error: The named reference IAUC8812 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Brown2013 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference TNOsCool8 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Brown2017 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Johnston was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Hainaut2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference AstDys was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference cowen was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference MPEC2002-V08 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference spitzer was invoked but never defined (see the help page).
  15. ^ 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 UK126)', Icarus (forthcoming, available online 30 March 2019) Archived 7 April 2019 at the Wayback Machine DOI: 10.1016/j.icarus.2018.12.037,