| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Ursa Major |
| Right ascension | 10h 22m 19.7s |
| Declination | +41° 29' 58" |
| Apparent magnitude (V) | +3.06 |
| Distance | 249 ± 14 ly (76 ± 4 pc) |
| Spectral type | M0III |
| Other designations | |
Mu Ursae Majoris (μ UMa, μ Ursae Majoris) is a star in the constellation Ursa Major. It also has the proper names Tania Australis (former Tania australis[1]) meaning "the Southern (star) of Tania." The word Tania comes from the Arabic phrase (al-Qafzah) al-Thāniyah meaning "the Second (Leap)" (the distinctions "southern" (australis) is added in Latin), Alkafzah Borealis, and El Phekrah[2] comes from the Arabic phrase al-Fiqrah (al-Thāniyah) meaning "(the Second) Vertebra". With Lambda Ursae Majoris, they were Chung Tae （中台）, the Middle Dignitary, in Chinese astronomy.[3]
Mu Ursae Majoris is a M-type red giant with a mean apparent magnitude of 3.0m. It is approximately 250 light years from the Earth. It is classified as a Semiregular variable star and its brightness varies from magnitude 2.99m to 3.33m.
Spectroscopically it has been determined that this is a double star with a companion a mere 1.5 AU from the primary with a rotation period of 230 days.