Third Tuesday 2017-02: Barnard's Star Event Cache

Barnard's Star is a very-low-mass red dwarf about six light-years away from Earth in the constellation of Ophiuchus. It is the fourth-closest known individual star to the Sun (after the three components of the Alpha Centauri system) and the closest star in the Northern Hemisphere. Despite its proximity, at a dim apparent magnitude of about nine, it is not visible with the unaided eye; however, it is much brighter in the infrared than it is in visible light.

The star is named after the American astronomer E. E. Barnard. He was not the first to observe the star (it appeared on Harvard University plates in 1888 and 1890), but in 1916 he measured its proper motion as 10.3 arcseconds per year, which remains the largest proper motion of any star relative to the Solar System.

Barnard's Star is among the most studied red dwarfs because of its proximity and favorable location for observation near the celestial equator. Historically, research on Barnard's Star has focused on measuring its stellar characteristics, its astrometry, and also refining the limits of possible extrasolar planets. Although Barnard's Star is an ancient star, it still experiences star flare events, one being observed in 1998.

The star has also been the subject of some controversy. For a decade, from the early 1960s to the early 1970s, Peter van de Kamp claimed that there were one or more gas giants in orbit around it. Although the presence of small terrestrial planets around Barnard's Star remains a possibility, Van de Kamp's specific claims of large gas giants were refuted in the mid-1970s.