39890 Bobstephens
Main-belt asteroid
From Wikipedia, the free encyclopedia
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]
(American astronomer)[2]
| Discovery[1] | |
|---|---|
| Discovered by | P. Pravec |
| Discovery site | Ondřejov Obs. |
| Discovery date | 23 March 1998 |
| Designations | |
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] | |
Orbit and classification
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]
Physical characteristics
Rotation period
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]
Diameter and albedo
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]
Naming
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]
