Lalande 21185

Lalande 21185 is a dim red dwarf star which is the fourth closest system to our Sun, after Alpha Centauri, Barnard's Star and Wolf 359. It is located about 8.3 light-years away in the constellation Ursa Major. It's coordinates are (11:03:20.19+35:58:11.55, ICRS 2000.0) . It is named for its discoverer.

This star generated considerable excitement in 1996 when the discovery of associated planets was announced. "This cool and dim, main sequence red dwarf (M2.1 Vne) has about 46 percent of Sol's mass (RECONS estimate), 46 percent of its diameter (Johnson and Wright, 1983, page 671), but less than 6/1,000th of its brightness. The star is less enriched in elements heavier than hydrogen ("metals") compared to our Sun, with around 63 percent of Sol's abundance of iron (Cayrel de Strobel et al, 1991, page 292). It is suspected to have at least one, but perhaps as many as three, Jupiter-class planets."(Arnold O. Benz, Institute of Astronomy, ETH Zurich)

Gatewood, G. D. "Lalande 21185," Bulletin of the Aerican Astronomical Society, 28, 885 (1996).

Discovery of Lalande 21185

The star Lalande 21185 " was first listed by Joseph-JÈrome Lefrançais de Lalande (1732-1807), who became director of the Paris Observatory in 1795, produced the most comprehensive catalog for his time of 47,390 star positions (the Histoire CÈleste Française) in 1801, and was actually the first person to add Flamsteed numbers to designate the brighter stars within each constellation in a French edition of John Flamsteed's (1645-1719) star catalog." http://www.solstation.com/stars/la21185.htm)

Gatewood, G. D. "Lalande 21185," Bulletin of the Aerican Astronomical Society, 28, 885 (1996).

Wolf 359

This extremely faint red dwarf star is the third closest to Sol after Alpha Centauri 3 and Barnard's Star. It is located only about 2.4 pc (7.8 light-years) away in the east central part (10:56:29+07:00.7, ICRS 2000.0) of Constellation Leo, the Lion -- south of Chertan or Coxa (Theta Leonis). However, the star is much too dim to be visible to the naked eye. It was discovered photographically by Max (Maximilian Franz Joseph Cornelius) Wolf (1863-1932), a pioneer of astrophotography who discovered hundreds of variable stars and asteroids, and about 5,000 nebulae by analyzing photographic plates and developing the "dry plate" in 1880 and the "blink comparator" in 1900 with the Carl Zeiss optics company in Jena, Germany. (Solstation)

Wolf 359 is comparable to the fainter companion star Gliese 623b at the right of the NASA image at left. Both it and the brighter Gliese 623a are red dwarfs. Wolf 359's position in the constellation Leo is near the ecliptic. It is characterized as a "flare star". Its closest neighbor is Ross 128, 1.16 pc or 3.79 ly away. Wolf 359 的亮度与图中左侧 NASA 图像右下方较暗的伴星 Gliese 623b 相当。两者都是红矮星，其中 Gliese 623a 更亮。Wolf 359 位于天琴座，接近黄道。它被描述为一种‘耀星’。其最近的邻居是 Ross 128，距离为 1.16 pc 或 3.79 光年。

"A very cool, main sequence red dwarf (M5.8Ve), Wolf 359 is our Sun's dimmest stellar neighbor within 10 ly, with less than 2/100,000th of Sol's luminosity. If our Sun, Sol, were replaced by Wolf 359, then an observer on Earth would need a telescope to see its round shape clearly, and daylight would be very dim with only ten times the brightness of full moonlight with Sol. On the other hand, Wolf 359 is a Flare Star (that has been designated with the variable star name CN Leonis) and so can brighten dramatically from time to time. Flares on Wolf 359, however, are rarer and not as violent as those observed on Proxima Centauri, Kruger 60 B, or UV Ceti."(solstation)

• http://www.solstation.com/stars/wolf359.htm
• http://en.wikipedia.org/wiki/Wolf_359