V1054 Ophiuchi
Coordinates: 
16h 55m 32.0s, −08° 21′ 30″
V1054 Ophiuchi, together with the star Gliese 643, is a nearby quintuple star system, located in constellation Ophiuchus at 21.05 light-years. It consists of five stars, all of which are red dwarfs.
Overview
V1054 Ophiuchi/Gliese 643 has the largest number of stars of all star systems, located within 10 pc from Earth. It is also the nearest quintuple star system (the next nearest star systems with at least five stars are GJ 2069 (quintuple) at 41.8 light-years, and Castor (sextuple) at 51.6 light-years), and only quintuple star system within 10 pc.
The system consists of three widely separated parts:
Hierarchy of the system is following:
System's five components are:
The brightest and most massive of this five stars is V1054 Ophiuchi A. Close binary subsystem V1054 Ophiuchi B is more massive than V1054 Ophiuchi A, however, its total visual magnitude is 0.1 mag fainter than V1054 Ophiuchi A's visual magnitude.
1781 Van Biesbroeck
1781 Van Biesbroeck, provisional designation A906 UB, is an asteroid from the inner regions of the asteroid belt. It was discovered on 17 October 1906 by German astronomer August Kopff at Heidelberg Observatory in southern Germany.
The asteroid orbits the Sun at a distance of 2.1–2.7 AU once every 3 years and 9 months (1,355 days). Its orbit shows an eccentricity of 0.11 and is tilted by 7 degrees to the plane of the ecliptic. Little is known about the asteroids size, composition, albedo and rotation, despite having a well-observed orbit with the lowest possible uncertainty (a condition code of 0) and an observation arc that spans over a period of more than a century. In addition, it is unknown whether the member of the Vesta family of asteroids is in fact a V/J-type, or if it is an unrelated interloper, as currently assumed to be more likely.
The minor planet was named after renowned Belgian–born observational astronomer George Van Biesbroeck, who naturalized as U.S. citizens in 1922. He specialized in the observation of double stars, variable stars, comets and asteroids, of which he discovered sixteen at the U.S. Yerkes Observatory in Williams Bay, Wisconsin, between 1922 and 1939. In 1961 he published the Van Biesbroeck's star catalog of low-mass, low-luminosity stars. The mountain Van Biesbroeck near the McDonald Observatory, the lunar crater Van Biesbroeck, and most notably the red dwarf Van Biesbroeck's Star, were also named in his honour. There are very few stars stars named after people. The George Van Biesbroeck Prize, awarded by the American Astronomical Society for achievements in astronomy, also bears his name.
Van Biesbroeck (crater)
Van Biesbroeck is a small lunar impact crater that interrupts the southern rim of the lava-flooded crater Krieger, in the Oceanus Procellarum. The crater is circular and symmetrical, with sloping inner walls that run down to a small interior floor. Van Biesbroeck was designated Krieger B before the IAU gave it a unique name.
See also
References
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