Lalande 21185


Catalog numbers:
     Lalande (LAL) 21185, Gliese (Gl) 411, Giclas (G) 119-52, Henry Draper (HD) 95735, Bonner Durchmusterung (BD) +362147, Luyten Half-Second (LHS) 37, Vyssotsky McCormick (McC) 594, Hipparcos Input Catalog (HIC) 54035, AGK3 Reference (AGK3R) 9911, Smithsonian Astrophysical Observatory (SAO) 62377, New Suspected Variable (NSV) 18593
Age: 3000 to 10 000 million years
Heavy element abundance: 63% of Sol
Source for heavy element abundance: J.R. Mould's Spectral Analysis
Arity: singular
Points of interest:
     The z-component of Lalande 21185's velocity suggests that it's from the galactic halo population; however, J.R. Mould's spectral analysis (printed in vol. 226, page 923 of the Astrophysical Journal (1978)) says that the ratio of iron to hydrogen in the star is a whopping 60% of our sun's iron-to-hydrogen ratio, which is awfully iron-rich for a halo population star.  The presence of emission lines in the star's spectrum would support the idea that this is a decently heavy-element-rich star as well.
     Wobbles in Lalande 21185's position were once thought to indicate an unseen object orbiting it, but subsequent analysis showed that no such wobbles were occurring.

Right Ascension and Declination: 11h3m20.228s, +35°58'11.24" (epoch 2000.0)
Distance from Sol: 8.312 light-years (2.548 parsecs)
Standard error in distance: 0.2314%
Source for distance: Hipparcos
Celestial (X,Y,Z) coordinates in ly: -6.523, 1.646, 4.882
Galactic (X,Y,Z) coordinates in ly: -3.359, -0.320, 7.596
Proper motion: 4.807 arcsec/yr (186.8° from north)
Radial Velocity: -84.3 km/sec
Source for proper motion and radial velocity: Gliese
Galactic (U,V,W) velocity components in km/s: 45.67, -53.58, -74.30

What do all these fields mean?

Spectral class: M2n
Luminosity Class: V
Apparent visual magnitude: +7.50
Absolute visual magnitude: +10.46
Visual luminosity: 0.00568 x Sol
Variable type: BY Draconis (rotating variable)
Color indices: B-V= +1.51, U-B= +1.12, R-I= +0.92
Mass: 0.403 x Sol
Source for mass: European Southern Observatory
Diameter: 0.393 x Sol
Source for diameter: European Southern Observatory
Comfort Zone (visual): 0.0754 A.U.s
Orbital period in CZ: 11.9058 days
Tidal index in CZ: 941.161
Angular size of star in sky in CZ: 2.781843 degrees

but not more than light-years away
Data for this star system were most recently updated on 8-September-2009.