Mu Leonis
K-type red giant with a confirmed exoplanet.
Mu Leonis, also designated Rasalas, is a star in the equatorial-northern constellation of Leo. With an apparent visual magnitude of 3.88, it is bright enough to be seen without optical aid. In 2014, an exoplanet was discovered orbiting this star.
Quick Facts
- Apparent magnitude
- 3.88
- Distance
- 38.1 pc
- Spectral type
- K-type red giant
- Age
- 5 billion years
Facts from the source article.
Did You Know?
- The star bore the traditional names Rasalas and Alshemali, both abbreviations of Ras al Asad al Shamaliyy, meaning 'north lion's head'.
- The IAU Working Group on Star Names approved the name Rasalas for this star on 12 September 2016.
Properties
Mu Leonis is an evolved K-type red giant star, believed to be on the red giant branch fusing hydrogen into helium in a shell around an inert helium core. Its spectrum shows stronger than normal absorption lines of cyanogen and calcium. It has about 1.5 times the Sun's mass and is estimated to be 5 billion years old. Its diameter is 11.74 times that of the Sun, and it shines with 57 times the Sun's luminosity at an effective temperature of 4,606 K.
Planetary system
In 2014, a planetary companion was announced around Mu Leonis, with at least 2.4 times the mass of Jupiter and an orbital period of 358 days. The planet was detected through radial velocity variations. A 2024 study using Gaia astrometry found a mass interpreted as a likely upper limit, with the authors noting that a large RUWE in the astrometric solution might be due to systematic calibration errors, indicating the object lies in the planetary-mass regime rather than being a brown dwarf.
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