In 1961 the astronomer

George Van Biesbroeck George A. Van Biesbroeck (or Georges-Achille Van Biesbroeck, , January 21, 1880 – February 23, 1974) was a Belgian–American astronomer. He worked at observatories in Belgium, Germany and the United States. He specialized in the observation o ...

published a catalog of low luminosity stars discovered using the Otto Struve refractor telescope of the

McDonald Observatory McDonald Observatory is an astronomical observatory located near unincorporated community of Fort Davis in Jeff Davis County, Texas, United States. The facility is located on Mount Locke in the Davis Mountains of West Texas, with additional faci ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

Survey and catalog

This survey is similar to earlier dim star surveys that were done by

Max Wolf Maximilian Franz Joseph Cornelius Wolf (21 June 1863 – 3 October 1932) was a German astronomer and a pioneer in the field of astrophotography. He was the chairman of astronomy at the University of Heidelberg and director of the Heidelberg-K� ...

and

Frank Elmore Ross Frank Elmore Ross (April 2, 1874 – September 21, 1960) was an American astronomer and physicist. He was born in San Francisco, California and died in Altadena, California. In 1901 he received his doctorate from the University of California. ...

but using later equipment and techniques that could detect even fainter stars. The stars in this catalog are all low luminosity stars that appear near known high

proper motion Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...

stars in the telescope's field of view. The high proper motion indicates that the stars are close enough to

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

for a dim star to be seen with a large telescope. Presuming that these high proper motion stars might be

binary stars A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

with dim, previously undetected, companions, he took astrophotographs of the space around these stars looking for low luminosity stars that shared the high

proper motions Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable reference ...

of the primary star. In general, the primary stars were too dim for a direct measurement of their distance by measuring their

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

at that time. The stars in this catalog are identified by the designation; ''VB''. The original list ended at 12 with most identified as gravitationally bound in a binary or multiple star system. He also identified an additional 17 known high

stars he later found to have low luminosity stars in the field of view of the bright star. Many of these stars were found to be optical

double stars In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a ...

, not gravitationally bound to another star, and not known to be part of a binary system. Most of the stars in this catalog are type K and M,

red dwarf A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs are ...

, stars, some with exceptionally low mass and luminosity. Three of the stars are type DC,

white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...

, stars. The star from this catalog that is known to be closest to Earth is

VB 10 VB 10 or Van Biesbroeck's star is a small and dim red dwarf located in the constellation Aquila. It is part of a binary star system. VB 10 is historically notable as it was the least luminous and least massive known star from its disco ...

, at about 19 light years distance. The original 1961 catalog has been updated for this table using the latest coordinates from

SIMBAD SIMBAD (the Set of Identifications, Measurements and Bibliography for Astronomical Data) is an astronomy, astronomical database of objects beyond the Solar System. It is maintained by the Centre de données astronomiques de Strasbourg (CDS), Fr ...

as many of these objects have moved a considerable distance away from their 1961 positions. The original object designations for the primary stars are used but modified to be consistent with

standards where necessary. One primary star was incorrectly identified and two primary stars could not be positively identified from the original catalog.

Significance

This catalog of stars is significant not only for the intrinsic features of the stars themselves but also for the stars proximity to

. These low mass, low luminosity stars close by are uniquely situated for exo-planetary searches using

astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, th ...

or optical methods. The low mass of the star enables observers on

to see a large motion of the star for a given planetary mass. The low luminosity of the stars makes a direct optical or infrared telescopic survey for orbiting objects, such as planets, near the star possible. A notable member of this group is

, discovered in 1944. This star was the least massive and dimmest star known at the time of its discovery. Based on a discovery claim made in 2009,

would have become the first star to have an extrasolar planet detected using

, however this claim was later refuted.

Notes

References

{{Portal bar, Astronomy, Stars, Outer space Astronomical catalogues of stars Astronomical surveys

Survey and catalog

Significance

See also

Notes

References