11 Ursae Minoris


11 Ursae Minoris is a single star located approximately 410 light-years away in the northern circumpolar constellation of Ursa Minor. The star is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.15. It is moving closer to the Earth with a heliocentric radial velocity of −17.8 km/s.

Stellar properties

This is an aging K-type giant star with a stellar classification of K4 III. It is 600 million years old with twice the mass of the Sun. As a consequence of exhausting the hydrogen at its core, the star has expanded to 29 times the Sun's radius. It is radiating 250 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,253 K.

Nomenclature

11 Ursae Minoris is the star's Flamsteed designation. It is sometimes named Pherkard or Pherkad Minor, the latter name to distinguish it from Pherkad which is γ Ursae Minoris. It has also been designated as γ1 Ursae Minoris, in which case the brighter Pherkad is called γ2 Ursae Minoris, but these names are rarely used.

Planetary system

11 Ursae Minoris has a detected planet discovered in August 2009. 11 Ursae Minoris b was discovered during a radial velocity survey of 62 K type red giant stars using the 2m Alfred Jensch telescope of the Thuringian State Observatory in Germany.
A newer mass measurement of the host star implies a larger planetary mass of, which would make 11 Ursae Minoris b a low-mass brown dwarf.