(79983) 1999 DF9
Trans-Neptunian object of the Kuiper belt
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(79983) 1999 DF9 (provisional designation 1999 DF9) is a trans-Neptunian object of the Kuiper belt, classified as a non-resonant cubewano, that measures approximately 270 kilometers in diameter.
| Discovery[1] | |
|---|---|
| Discovered by | J. X. Luu C. Trujillo D. C. Jewitt |
| Discovery site | Kitt Peak National Obs. |
| Discovery date | 20 February 1999 |
| Designations | |
| (79983) 1999 DF9 | |
| 1999 DF9 | |
| TNO[1] · cubewano[2][3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 17.06 yr (6,231 days) |
| Aphelion | 53.567 AU |
| Perihelion | 39.830 AU |
| 46.698 AU | |
| Eccentricity | 0.1471 |
| 319.12 yr (116,560 days) | |
| 19.489° | |
| 0° 0m 11.16s / day | |
| Inclination | 9.8105° |
| 334.84° | |
| 178.63° | |
| Known satellites | 0 |
| Physical characteristics | |
| Dimensions | 265 km (calculated)[4] 306 km[3] |
| 6.65 h[5] | |
| 0.10 (assumed)[4] | |
| BâV = 0.920±0.060[6] VâR = 0.710±0.050[6] VâI = 1.360±0.060[6] | |
| 5.797±0.110 (R)[7] · 6.0[1][4] | |
Discovery
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.[8] As no precoveries were taken, the minor planet's observation arc begins with its discovery observation in 1999.[8]
Classification and orbit
The minor planet is a classical Kuiper belt object or "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 39.8â53.6 AU once every 319 years and 1 month (116,560 days). Its orbit has an eccentricity of 0.15 and an inclination of 10° with respect to the ecliptic.[1] This makes it a relatively eccentric body for a classical Kuiper belt object, which typically have low-eccentricities of 0.10 or less.
Physical characteristics
In February 2001, a rotational lightcurve was published for this minor planet from photometric observations by Portuguese astronomer Pedro Lacerda and the discovering astronomer Jane Luu. Lightcurve analysis gave a relatively short rotation period of 6.65 hours with a brightness variation of 0.40 magnitude (U=2).[5]
The Collaborative Asteroid Lightcurve Link assumes a low albedo of 0.10 and calculates a mean-diameter of 265 kilometers, based on an absolute magnitude of 6.0,[4] while Johnston's Archive give a diameter of 306 kilometers for an albedo of 0.09.[3]
Numbering and naming
This minor planet was numbered by the Minor Planet Center on 4 May 2004.[9] As of 2025, it has not been named.[8]
