39890 Bobstephens (

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calcu ...

) is a stony

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

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 The Ondřejov Observatory (; cs, Observatoř Ondřejov) is the principal observatory of the Astronomical Institute () of the Academy of Sciences of the Czech Republic. It is located near the village of Ondřejov, southeast of Prague, Czech R ...

near Prague in the Czech Republic. It was named for American astronomer

Robert Stephens Sir Robert Graham Stephens (14 July 193112 November 1995) was a leading English actor in the early years of Britain's Royal National Theatre. He was one of the most respected actors of his generation and was at one time regarded as the natur ...

Orbit and classification

Bobstephens orbits the Sun in the

central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

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. It was first imaged at Steward Observatory in 1995. This

precovery In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens mos ...

extends the body's observation arc by 3 years prior to its official discovery observation.

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 The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 9.55 hours with a brightness variation of 0.20 magnitude ().

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.

Naming

This minor planet was named for Californian amateur astronomer and photometrist

Robert D. Stephens Robert D. Stephens (born 1955) is an American amateur astronomer and a prolific photometrist of minor planets at the Center for Solar System Studies , Rancho Cucamonga in California, United States. Career By profession, Stephens is a Certif ...

(born 1955), who is an expert in lightcurve

photometry Photometry can refer to: * Photometry (optics), the science of measurement of visible light in terms of its perceived brightness to human vision * Photometry (astronomy), the measurement of the flux or intensity of an astronomical object's electrom ...

of minor planets since 1999. The official naming citation was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

on 24 July 2002 ().

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Minor Planet Center * * {{DEFAULTSORT:Bobstephens 039890 Discoveries by Petr Pravec Named minor planets 19980323