Groombridge 1830 (also known as 1830 Groombridge or Argelander's Star) is a star in the constellation Ursa Major. Description It is a yellow-hued class G8 subdwarf catalogued by British astronomer Stephen Groombridge with the Groombridge Transit Circle between 1806 and the 1830s and published posthumously in his star catalog, Catalogue of Circumpolar Stars (1838). Its high proper motion was noted by Friedrich Wilhelm Argelander in 1842. It is from the Sun as measured by the Gaia spacecraft, which, as the distance is nearly 10 parsecs, means its absolute magnitude is almost equal to its apparent magnitude. It is a member of the galactic halo; such stars account for only 0.1 to 0.2 percent of the stars near the Sun. Like most halo stars, it has a low abundance of elements other than hydrogen and helium—what astronomers term a metal-poor star. Once suspected of being a binary star with a period of 175 days, current consensus is that it is single. Previous suspected observations of a stellar companion were probably "superflares"—analogous to the Sun's solar flares, but hundreds to millions of times more energetic. It had one of the first nine identified superflares. Proper motion When discovered, it had the highest proper motion of any star known, replacing 61 Cygni in that department. Later it dropped to second place after the discovery of Kapteyn's Star, and still later to third place after the discovery of Barnard's Star. It is considerably farther away than either of those stars, however, which means its transverse velocity is greater. See also List of star systems within 25–30 light-years References External links SolStation.com: Groombridge 1830 AN 19 (1842) 393/394 (in German) AN 20 (1843) 163/164 (in German) AN 20 (1843) 279/280 Ursa Major (constellation) Binary stars G-type subdwarfs Groombridge, 1830 1830 103095 High-proper-motion stars Stars with proper names 4550 057939 Durchmusterung objects 0451 TIC objects