Discovery [1] | |
---|---|
Discovered by | P. Pravec |
Discovery site | Ondřejov Obs. |
Discovery date | 23 March 1998 |
Designations | |
(39890) Bobstephens | |
Named after |
Robert D. Stephens (American astronomer) [2] |
1998 FA3 | |
main-belt · ( middle) | |
Orbital characteristics [1] | |
Epoch 4 September 2017 ( JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 21.25 yr (7,760 days) |
Aphelion | 3.1534 AU |
Perihelion | 2.0287 AU |
2.5910 AU | |
Eccentricity | 0.2170 |
4.17 yr (1,523 days) | |
201.46 ° | |
0° 14m 10.68s / day | |
Inclination | 5.4950° |
161.73° | |
95.752° | |
Physical characteristics | |
Dimensions | 2.06 km (calculated) [3] |
9.55±0.01 h [4] | |
0.20 (assumed) [3] | |
S [3] | |
15.8 [3] · 15.9 [1] | |
39890 Bobstephens ( provisional designation 1998 FA3) is a stony asteroid from the middle region of the asteroid belt, approximately 2 kilometers in diameter. The asteroid was discovered on 23 March 1998, by Czech astronomer Petr Pravec at Ondřejov Observatory near Prague in the Czech Republic. [5] It was named for American astronomer Robert Stephens. [2]
Bobstephens orbits the Sun in the central main-belt at a distance of 2.0–3.2 AU once every 4 years and 2 months (1,523 days). Its orbit has an eccentricity of 0.22 and an inclination of 5 ° with respect to the ecliptic. [1] It was first imaged at Steward Observatory in 1995. This precovery extends the body's observation arc by 3 years prior to its official discovery observation. [5]
In August 2008, a rotational lightcurve of Bobstephens was obtained from photometric observations by American amateur astronomer Daniel Coley at the Center for Solar System Studies in California. Light-curve analysis gave a rotation period of 9.55 hours with a brightness variation of 0.20 magnitude ( U=2). [4]
The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.06 kilometers with an absolute magnitude of 15.8. [3]
This minor planet was named for Californian amateur astronomer and photometrist Robert D. Stephens (born 1955), who is an expert in lightcurve photometry of minor planets since 1999. [2] The official naming citation was published by the Minor Planet Center on 24 July 2002 ( M.P.C. 46112). [6]