(55637) 2002 UX25
Perihelion 36.485 AU | | |
42.488 AU | ||
Eccentricity | 0.1413 | |
276.95 yr (101,157 days) | ||
Average orbital speed | 4.54 km/s | |
295.71° | ||
0° 0m 12.96s / day | ||
Inclination | 19.484° | |
204.68° | ||
≈ 5 September 2066[4] ±3 days | ||
279.00° | ||
Known satellites | 1 (ø: 190–260 km)[5][6] | |
Physical characteristics | ||
Mean diameter | 665±29 km[7] 659±38 km Synodic rotation period 14.382±0.001 h[9] | |
0.107+0.005 −0.008[7] 0.1±0.01 | ||
19.8 [11] | ||
3.87±0.02,[9] 4.0[1] | ||
(55637) 2002 UX25 (
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.[13] 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.[14]
It was discovered on 30 October 2002, by the Spacewatch program.[15]
Numbering and naming
This
Classification
2002 UX25 has a perihelion of 36.7 AU,[1] which it will next reach in 2065.[1] As of 2020, 2002 UX25 is 40 AU from the Sun.[11]
The Minor Planet Center classifies 2002 UX25 as a cubewano[2] while the Deep Ecliptic Survey (DES) classifies it as scattered-extended.[3] The DES using a 10 My integration (last observation: 2009-10-22) shows it with a minimum perihelion (qmin) distance of 36.3 AU.[3]
It has been observed 212 times with precovery images dating back to 1991.[1]
Physical characteristics
A variability of the visual brightness was detected which could be fit to a period of 14.38 or 16.78 h (depending on a single-peaked or double peaked curve).[18] The light-curve amplitude is ΔM = 0.21±0.06.[9]
The analysis of combined thermal radiometry of 2002 UX25 from measurements by the
−0.008. Assuming equal albedos for the primary and secondary it leads to the size estimates of ~664 km and ~190 km, respectively. If the albedo of the secondary is half of that of the primary the estimates become ~640 and ~260 km, respectively.[6] Using an improved thermophysical model slightly different sizes were obtained for UX25 and its satellite: 659 km and 230 km, respectively.[8]
2002 UX25 has red featureless spectrum in the visible and near-infrared but has a negative slope in the K-band, which may indicate the presence of the
Composition
With a density of 0.82 g/cm3, assuming that the primary and satellite have the same density, 2002 UX25 is one of the largest known solid objects in the Solar System that is less dense than water.[12] Why this should be is not well understood, because objects of its size in the Kuiper belt often contain a fair amount of rock and are hence pretty dense. To have a similar composition to others large KBOs, it would have to be exceptionally porous, which was believed to be unlikely given the compactability of water ice;[6] this low density thus astonished astronomers.[12] Studies by Grundy et al. suggest that at the low temperatures that prevail beyond Neptune, ice is brittle and can support significant porosity in objects significantly larger than 2002 UX25, particularly if rock is present; the low density could thus be a consequence of this object failing to warm sufficiently during its formation to significantly deform the ice and fill these pore spaces.[19]
What | Density (g/cm3) |
Notes |
---|---|---|
Settled snow | 0.2–0.3 | [20] |
Slush/firn | 0.7–0.8 | [20] |
2002 UX25 | 0.82 | [6] |
Glacier ice | 0.83–0.92 | [20] |
Tethys | 0.984 | [21] |
Liquid water | 1 | [20] |
Satellite
Discovery | |
---|---|
Discovered by | Brown et al. |
Discovery date | 2007 |
Orbital characteristics | |
4750±40 km[22] | |
Eccentricity | 0.18±0.02[22] |
8.3095 d (prograde)[22] | |
Inclination | 63.1°[22] |
Satellite of | 2002 UX25 |
Physical characteristics | |
Mean radius | 105±15 km[23] |
The discovery of a
This moon is estimated to be 210±30 km in diameter.[7] Assuming the same albedo as the primary, it would have a diameter of 190 km, assuming an albedo of 0.05 (typical of other cold, classical KBOs of similar size) a diameter of 260 km.[6]
References
- ^ a b c d e f g "JPL Small-Body Database Browser: 55637 (2002 UX25)" (2017-01-16 last obs.). Jet Propulsion Laboratory. Retrieved 24 February 2018.
- ^ a b "MPEC 2009-C70 :Distant Minor Planets (2009 FEB. 28.0 TT)". Minor Planet Center. 10 February 2009. Retrieved 5 July 2011.
- ^ Marc W. Buie. "Orbit Fit and Astrometric record for 55637"(2009-10-22 using 60 observations). SwRI (Space Science Department). Retrieved 12 March 2009.
- 3-sigma.)
- ^ a b c Daniel W. E. Green (22 February 2007). "IAUC 8812: Sats OF 2003 AZ_84, (50000), (55637), (90482)". International Astronomical Union Circular. Archived from the original on 19 July 2011. Retrieved 5 July 2011.
- ^ S2CID 17839077.
- ^ S2CID 119261700.
- ^ .
- ^ a b c d e f "(55637) 2002 UX25". www.johnstonsarchive.net. Archived from the original on 28 June 2012. Retrieved 21 May 2020.
- ^ S2CID 54776793.
- ^ a b "AstDys (55637) 2002UX25 Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 12 December 2020.
- ^ S2CID 123788849.
- ISBN 978-0-8165-2755-7.
- ^ 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,
- ^ Marsden, Brian G. (1 November 2002). "MPEC 2002-V08 : 2002 UX25". IAU Minor Planet Center. Harvard-Smithsonian Center for Astrophysics. Retrieved 5 July 2011.
- ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.
- ^ "55637 (2002 UX25)". Minor Planet Center. Retrieved 12 December 2020.
- ^ Rousselot, P.; Petit, J.-M.; Poulet, F.; Sergeev, A. Photometric study of Centaur (60558) 2000 EC98 and trans-neptunian object (55637) 2002 UX25 at different phase angles, Icarus, 176, (2005) pp. 478–491.Abstract.
- ^ "The Mutual Orbit, Mass, and Density of Transneptunian Binary" (PDF). 7 April 2019. Archived from the original (PDF) on 7 April 2019. Retrieved 21 May 2020.
- ^ a b c d "Typical densities of snow and ice (kg/m3)". Archived from the original on 1 January 2014. Retrieved 21 May 2020.
- ^ Roatsch Jaumann et al. 2009, p. 765, Tables 24.1–2
- ^ a b c d "2002 UX25 System parameters". Will Grundy. Retrieved 29 August 2023.
- ^ "(55637) 2002 UX25". Retrieved 28 July 2023.
- ^ Distant EKO The Kuiper Belt Electronic newsletter, March 2007
External links
- MPEC 2002-V08
- Astronomers surprised by large space rock less dense than water, Ron Cowen, Nature, 13 November 2013
- Scientist finds medium sized Kuiper belt object less dense than water, Bob Yirka, Phys.org, 14 November 2013
- (55637) 2002 UX25 at AstDyS-2, Asteroids—Dynamic Site
- (55637) 2002 UX25 at the JPL Small-Body Database