(48639) 1995 TL8

Infobox Planet | discovery=yes | physical_characteristics=yes
bgcolour=#FFFFC0
name=mp|(48639) 1995 TL|8
discoverer=A. Gleason (Spacewatch)
discovered=October 15, 1995 and November 9, 2002 ("moon")
mp_name=mp|(48639) 1995 TL|8
alt_names="none"
mp_category=Scattered disk object
epoch=March 6, 2006 (JD 2453800.5)
semimajor=7,814.8 Gm (52.239 AU)
perihelion=5,986.3 Gm (40.016 AU)
aphelion=9,643.4 Gm (64.462 AU)
eccentricity=0.234
period=137,907 d (377.57 a)
inclination=0.2°
asc_node=260.7°
arg_peri=83.4°
mean_anomaly=33.6°
avg_speed=4.06 km/s
satellites=1
dimensions=~350 and ~160 km (binary)
mass=~4.5 and ~0.4 e|19 kg
density=2.0? g/cm³
surface_grav=~0.10 and ~0.04 m/s²
escape_velocity=~0.18 and ~0.08 km/s
sidereal_day=? d
spectral_type=?
abs_magnitude=5.28 and 6.98
albedo=0.10?
single_temperature=~38 K

mp|(48639) 1995 TL|8 (also written (48639) 1995 TL8) is a trans-Neptunian object of the Scattered disk object (SDO) subclass, and possesses a very large satellite.

Discovery

Discovered in 1995 by Arianna E. Gleason as part of the Spacewatch project, it was the first of the bodies presently classified as a Scattered disk object (SDO) to be discovered, preceding the SDO prototype mpl|(15874) 1996 TL|66 by almost a year.

atellite

A companion was discovered by Denise C. Stephens and Keith S. Noll from observations with the Hubble Space Telescope taken on November 9, 2002 and announced on October 5, 2005. The satellite, designated S/2002 (48639) 1, is relatively large, having a likely mass of about 10% of the primary. Its orbit has not been determined, but it was at a separation of only about 420 km to the primary at the time of discovery, with a possible orbital period of about half a day and an estimated diameter of 161 km [http://www.johnstonsarchive.net/astro/astmoons/am-48639.html] .

General

mp|(48639) 1995 TL|8 is unusual in being one of the few objects with a perihelion beyond 40 AU, well outside of Neptune's orbit.

The diameters given are derived from an albedo guess of 0.09, being typical for trans-Neptunian objects [http://www.johnstonsarchive.net/astro/tnoslist.html] .

External links

* [http://www.cfa.harvard.edu/iau/mpec/J99/J99L24.html 1999 MPEC listing]
* [http://www.cfa.harvard.edu/iau/mpec/K00/K00Q15.html 2000 MPEC listing]
* [http://www.johnstonsarchive.net/astro/tnoslist.html list of known TNOs, including size estimates]
* [http://www.johnstonsarchive.net/astro/astmoons/am-48639.html Johnston Archive entry about the satellite]
* [http://www.cfa.harvard.edu/iau/lists/MPLists.html IAU minor planet lists]