|
Lalande 21185 is a red dwarf in the constellation of Ursa Major. Although relatively close by, it is only magnitude 7 in visible light and thus is too dim to see with the unaided eye. The star is visible through a small telescope.〔 At approximately 〔 away it is one of the nearest stars to the Solar System; only the Alpha Centauri system, Barnard's Star, and Wolf 359 and the brown dwarfs Luhman 16 and WISE 0855−0714 are known to be closer.〔 Because of its proximity it is a frequent subject for astronomical surveys and other research and thus is known by numerous other designations. Research papers most commonly use the designations BD+36 2147, Gliese 411, and HD 95735 to refer to this star.〔(【引用サイトリンク】 title=SIMBAD query result: HD 95735 -- Flare Star )〕 In approximately 19,900 years Lalande 21185 will be at its closest distance of about 4.65 ly (1.43 pc) from the Sun.〔〔(【引用サイトリンク】 title=Annotations on HD 95735 object )〕 == History == The celestial coordinates of Lalande 21185 were first published in 1801 by French astronomer Jérôme Lalande of the Paris Observatory in the star catalog, ''Histoire Céleste Française''. The catalog sequence numbers for majority of the observed stars, including this one, were introduced in its 1847 edition by Francis Baily.〔Baily, Francis; Lalande, Joseph Jérôme Le Français de (1847). "Catalogue of those stars in the Histoire Celeste Francaise of Jerome Delalande, for which tables of reduction to the epoch 1800 habe been published by Prof. Schumacher". ''London (1847)''. Bibcode:(1847cshc.book.....B ). Google Books id: (oc0-AAAAcAAJ ). 〕 Today this star, along with a few others, is still commonly referred to by its Lalande catalog number.〔(Joseph-Jérôme de Lalande ) 〕 In May, 1857 Friedrich Wilhelm Argelander discovered high proper motion of the star. Sometimes it was called ''Argelander's second star''. (The "first" ''Argelander's star'' is Groombridge 1830, which high proper motion also was discovered by Argelander earlier—in 1842). Friedrich August Theodor Winnecke is reported to have made the first measurement of the star's parallax of .511 arc seconds in 1857-1858 and thus first identifying Lalande 21185 as the second-closest known star to the Sun, after the Alpha Centauri system.〔 Since that time better measurements have placed the star further away but it was the still the second-closest known star system until the discovery of two dim red dwarfs, Wolf 359 and Barnard's Star, in the early twentieth century using astrophotography. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lalande 21185」の詳細全文を読む スポンサード リンク
|