|Discovery date 20 February 1999|
Alternative names 1999 DF9
Observation arc 17.06 yr (6,231 days)
Absolute magnitude 6.1
|MPC designation (79983) 1999 DF9|
Minor planet category TNO · cubewano
Discovered 20 February 1999
|Discovered by J. X. Luu
D. C. Jewitt|
Discovery site Kitt Peak National Observatory
Discoverers Jane Luu, Chad Trujillo, David C. Jewitt
Similar S/2000 (1998 WW31) 1, (119951) 2002 KX14, 53311 Deucalion, 38083 Rhadamanthus, (15788) 1993 SB
(79983) 1999 DF9 is a trans-Neptunian object of the Kuiper belt, classified as a non-resonant cubewano, that measures approximately 265 kilometers in diameter. It was discovered on 20 February 1999, by American and British astronomers Jane Luu, Chad Trujillo and David C. Jewitt at the U.S. Kitt Peak National Observatory in Arizona.
The carbonaceous minor planet is a classical Kuiper belt object ("cubewano"), which are not in an orbital resonance with Neptune and do not cross the giant planet's orbit. It orbits the Sun at a distance of 39.8–53.7 AU once every 319 years and 7 months (116,731 days). Its orbit has an eccentricity of 0.15 and an inclination of 10° with respect to the ecliptic. This makes it a relatively eccentric body for a classical Kuiper belt object, which typically have low-eccentricities of 0.10 or less. As no precoveries were taken, the minor planet's observation arc begins with its discovery observation in 1999.
In 2006, a rotational light-curve was published for this minor planet from photometric observations by Portuguese astronomer Pedro Lacerda and the discovering astronomer Janue Luu. The light-curve gave a relatively short rotation period of 7000665000000000000♠6.65 hours with a brightness variation of 0.40 magnitude (U=2).
The Collaborative Asteroid Lightcurve Link assumes a low albedo of 0.10 and calculates a diameter of 265.2 kilometers, based on an absolute magnitude of 6.0. Due to its small size, it is unlikely to be classified as a dwarf planet.