Physical Properties
Lalande 21185 is a typical type-M red dwarf main sequence star with about 46% of the mass of the Sun and is much cooler than the Sun at 3,383 K. It is intrinsically dim with an absolute magnitude of 10.48, emitting most of its energy as infrared radiation. Lalande 21185 is a high-proper-motion star moving at about 5 arc seconds a year in an orbit perpendicular to the plane of the galaxy. The proportion of elements other than hydrogen and helium is estimated based on the ratio of iron to hydrogen in the star when compared to the Sun. The logarithm of this ratio is –0.20, indicating that the proportion of iron is about 10–0.20, or 63% of the Sun. The logarithm of the surface gravity is 4.8.
Lalande 21185 is listed as a BY Draconis type variable star in the General Catalogue of Variable Stars. It is identified by the variable star designation NSV 18593. Several star catalogs, including SIMBAD, also classify it as a flare star. This conclusion is not supported by the primary reference these catalogs all use. The observations made in this reference show that it is rather quiet in comparison to other stars of its variable type.
Lalande 21185 emits X-rays.
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