61 Ursae Majoris

61 Ursae Majoris (abbreviated as 61 UMa) is a single star located in the northern circumpolar constellation of Ursa Major. It has a yellow-orange hue and an apparent visual magnitude of 5.35, making it dimly visible to the naked eye. The star is situated 31.2 light-years away and is moving closer to Earth with a radial velocity of −5.2 km/s. Its proper motion is recorded at 0.381″ per year. Classification-wise, 61 UMa is a G8V star, a late G-type main-sequence star. It has been used as a spectral anchor point since 1943. With 93% the mass and 86% the radius of the Sun, it shares similar physical properties, including a solar-like metallicity. The star is approximately two billion years old, rotates with a projected velocity of 3.3 km/s (resulting in a 17.1-day period), and emits at 61% of the Sun's luminosity with an effective temperature of 5,488K. Historical observations noted potential variability in brightness during the 1950s, though this was later unconfirmed. It exhibits differential rotation, with varying periods across latitudes. The star’s active chromosphere shows persistent starspot activity and has been observed emitting X-rays following a flare event in 2013. No substellar companions or dust rings have been detected around 61 UMa. A radial velocity survey concluded no giant planets exist in its system. Notably, the star has a visual companion, a magnitude 11.35 star reported by O. Struve in 1850, which is now separated by 158.90″ at an angle of 86°. In popular culture, 61 Ursae Majoris features ...