Epsilon Ursae Minoris

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ε Ursae Minoris
Ursa Minor IAU.svg
Cercle rouge 100%.svg

Location of ε Ursae Minoris.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Minor
Right ascension 16h 45m 58.1s
Declination +82° 02' 14"
Apparent magnitude (V) +4.21
Distance 347 ± 25 ly
(106 ± 8 pc)
Spectral type G5III
Other designations
22 Ursae Minoris, HR 6322, HD 153751, BD+82 498, FK5 912, HIP 82080, SAO 2770, GC 22749, ADS 10242, CCDM 16460+8203

Epsilon Ursae Minoris (ε UMi, ε Ursae Minoris) is a triple star system in the constellation Ursa Minor. It is approximately 347 light years from Earth.

The primary component, Epsilon Ursae Minoris A, is an eclipsing spectroscopic binary. It is classified as a yellow G-type giant with a mean apparent magnitude of +4.21. In addition to light changes due to eclipses, the system is also classified as an RS Canum Venaticorum type variable star and its brightness varies from magnitude +4.19 to +4.23 with a period of 39.48 days, which is also the orbital period of the binary. The binary is orbited by a third component, Epsilon Ursae Minoris B, which is an 11th magnitude star, 77 arcseconds away in the sky.