Tuesday, July 3, 2007

Lalande 21185

Star type
g M2.1 Vne (cool and dim, main sequence red dwarf, flare star)

Distance from Earth
g 8.312 ly

Star Service No.
g NA

g Probably much older than our own 4.6-billion-year-old Sun but probably less than 10 billion years old

g 46%; 46%; 3000 K

Brightness (xSol)
g 0.568%

g 63%

Comparison to Sol
g See chart (similar to Proxima)

Picture of star
g See picture
g See picture at upper right of this page

Star system features
g NA

Known planets
g None, but suspected to have at least one, but perhaps as many as three, Jupiter-class planets; Closest to Lalande 21185, planetary candidate ("b") may lie within 2.2 AU to the star or around the inner boundary of the main asteroid belt in the Solar System, has about 90% of Jupiter's mass, a highly circular orbit (e~0.0), and a period of 5.8 years; second planet ("c") may lie about 11 AUs away in the first planet's orbital plane, with perhaps 1.6 Jupiter masses, a highly circular orbit (e~0), and a period of 30 years; if the second planet's mass has not been significantly underestimated, then there may be a third planet ("d") lying beyond 11 AUs with around one Jupiter mass and a longer orbital period. See painting of imagined world.

Habitable zone
g 0.074 AU, tidally locked, 11 day orbit. Flare star decreases chance of earth-like life. Probability of habitable planet is less than 0.1% (if satellite-stabilized).

Orbital map
g See map

View from star
g NA

Nearby stars
(Star systems with 10 light years)
g Wolf 359, 4.1 ly
g Ross 128, 6.5 ly
g DX Cancri, 6.7 ly
g BD+44 2051 A and WX Ursae Majoris (B), 7.6 ly
g Wolf 424 AB, 8.2 ly
g Groombridge 1618, 8.3 ly
g Sol, 8.3 ly
g AD Leonis, 8.5 ly
g Procyon 2, 9.6 ly
g LTT 12352, 9.7 ly

Map locating star system
Part of galaxy’s thick disk
g See stellar map
g See stellar map

Location in Earth sky
g Southeastern corner of Constellation Ursa Major and northwest of Alula Borealis (Nu Ursae Majoris); it is about three times too faint to be seen with the naked eye, however
g See sky map

Other names
g Gl 411
g Hip 54035
g HD 95735
g BD+36 2147
g SAO 62377
g LHS 37
g LTT 12960
g LFT 756
g Vys/McC 594
g G 119-52
g G 147-17
g GC 15183
g Lal 21185

Sci-fi mentions
g Rogue Queen (1951), novel by L. Sprague de Camp. Lalande 21185 is the sun of the planet Ormazd.
g Lalande 21185 (1966), novel by Janusz A. Zajdel.
g Across the Sea of Suns (1983), novel by Gregory Benford. Lalande 21185 is renamed Ra.
g Revelation Space stories by Alastair Reynolds (including "Galactic North"). The planet Zion orbits Lalande 21185.
g Star Corps (2006), novel by Ian Douglas. One of Lalande 21185's gas giants has an Earth-like moon where an alien race holds humans in slavery, resulting in a force of US Marines being sent in 2148 to free them.
g Civilization II: Test of Time, computer game. Lalande 21185 is mentioned.
g Frontier: Elite II and Frontier: First Encounters, computer games. In this series, Lalande 21185 is dedicated to heavy industry. With a colony based on the innermost planet of the system and a space station orbiting said planet, this industry-based system is more developed than most.
g Timemaster by Robert L. Forward has three astronauts creating a wormhole by voyaging there between 2043 and 2052

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