Mu Ursae Majoris

Mu Ursae Majoris is a binary star in the constellation of Ursa Major, and possibly part of a triple star system. It has the proper name Tania Australis, is its Bayer designation. An apparent visual magnitude of +3.06 places it among the brighter members of the constellation. Parallax measurements give a distance measurement of roughly, with a margin of error of 4%.

Stellar system

Mu Ursae Majoris is an evolved star that is currently in the red giant stage with a stellar classification of M0 IIIab. It has expanded to 75 times the radius of the Sun whilst the outer atmosphere has cooled to an effective temperature of 3,899 K, giving it the orange-red hued glow of an M-type star. Estimates of the luminosity range from 977–1,200 times that of the Sun. It is classified as a suspected variable star with a brightness variation from magnitude 2.99^m to 3.33^m.
This is a spectroscopic binary star system with a companion a mere 0.2 AU from the primary, with an orbital period of 230 days.
In addition to the inner pair, a proper motion companion has a 99% chance to be related to this system. It has a very low mass of just 0.1 solar masses, and a projected separation of 3,900 astronomical units.

μ Ursae Majoris is the star's Bayer designation. It can be abbreviated to abbreviated or.
It bore the traditional names Tania and Tania Australis. Tania comes from the Arabic phrase 'the Second Spring '. and Australis is Latin for 'the south side'. In 2016, the International Astronomical Union organized a Working Group on Star Names to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Tania Australis for this star.
In Chinese, 三台, meaning Three Steps, refers to an asterism consisting of Mu Ursae Majoris, Iota Ursae Majoris, Kappa Ursae Majoris, Lambda Ursae Majoris, Nu Ursae Majoris and Xi Ursae Majoris. Consequently, the Chinese name for Mu Ursae Majoris itself is 中台二.