(79983) 1999 DF9

(79983) 1999 DF9
Discovery [1]
Discovered byJ. X. Luu
C. Trujillo
D. C. Jewitt
Discovery siteKitt Peak National Obs.
Discovery date20 February 1999
(79983) 1999 DF9
1999 DF9
TNO[1] · cubewano[2][3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 2
Observation arc17.06 yr (6,231 days)
Aphelion53.567 AU
Perihelion39.830 AU
46.698 AU
319.12 yr (116,560 days)
0° 0m 11.16s / day
Physical characteristics
Dimensions265 km (calculated)[4]
306 km[3]
6.65 h[5]
0.10 (assumed)[4]
B–V = 0.920±0.060[6]
V–R = 0.710±0.050[6]
V–I = 1.360±0.060[6]
5.797±0.110 (R)[7] · 6.0[1][4]

(79983) 1999 DF9 is a trans-Neptunian object of the Kuiper belt, classified as a non-resonant cubewano, that measures approximately 270 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.[8] As no precoveries were taken, the minor planet's observation arc begins with its discovery observation in 1999.[8]

Classification and orbit[]

The carbonaceous 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 39.8–53.6 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 the Johnston's archive give a diameter of 306 kilometers for an albedo of 0.09.[3] Due to its small size, it is unlikely to be classified as a dwarf planet.

Numbering and naming[]

This minor planet was numbered by the Minor Planet Center on 4 May 2004.[9] As of 2018, it has not been named.[8]


  1. ^ a b c d e "JPL Small-Body Database Browser: 79983 (1999 DF9)" (2016-03-13 last obs.). Jet Propulsion Laboratory. Retrieved 1 June 2017.
  2. ^ Marc W. Buie. "Orbit Fit and Astrometric record for 79983". SwRI (Space Science Department). Retrieved 17 February 2018.
  3. ^ a b c Robert Johnston (7 October 2018). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 12 November 2018.
  4. ^ a b c d e "LCDB Data for (79983)". Asteroid Lightcurve Database (LCDB). Retrieved 31 August 2016.
  5. ^ a b Lacerda, Pedro; Luu, Jane (April 2006). "Analysis of the Rotational Properties of Kuiper Belt Objects". The Astronomical Journal. 131 (4): 2314–2326. arXiv:astro-ph/0601257. Bibcode:2006AJ....131.2314L. doi:10.1086/501047.
  6. ^ a b c Hainaut, O. R.; Boehnhardt, H.; Protopapa, S. (October 2012). "Colours of minor bodies in the outer solar system. II. A statistical analysis revisited". Astronomy and Astrophysics. 546: 20. arXiv:1209.1896. Bibcode:2012A&A...546A.115H. doi:10.1051/0004-6361/201219566.
  7. ^ Peixinho, N.; Delsanti, A.; Guilbert-Lepoutre, A.; Gafeira, R.; Lacerda, P. (October 2012). "The bimodal colors of Centaurs and small Kuiper belt objects". Astronomy and Astrophysics. 546: 12. arXiv:1206.3153. Bibcode:2012A&A...546A..86P. doi:10.1051/0004-6361/201219057.
  8. ^ a b c "79983 (1999 DF9)". Minor Planet Center. Retrieved 31 August 2016.
  9. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.

External links[]