Epsilon Muscae
Variable star in the constellation Musca
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Epsilon Muscae, Latinized from ε Muscae, is a red giant star of spectral type M5III in the constellation Musca.[5] It is a 4th magnitude star, visible to the naked eye under good observing conditions. It is about 330 light-years from the Earth.[2]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Musca[1] |
| Right ascension | 12h 17m 34.27564s[2] |
| Declination | −67° 57′ 38.6525″[2] |
| Apparent magnitude (V) | 4.0 – 4.3[3] |
| Characteristics | |
| Evolutionary stage | asymptotic giant branch[4] |
| Spectral type | M5 III[5] |
| Variable type | SRb[3] |
| Astrometry | |
| Radial velocity (Rv) | 7.1±0.7[6] km/s |
| Proper motion (μ) | RA: −230.607±0.187 mas/yr[2] Dec.: −26.206±0.263 mas/yr[2] |
| Parallax (π) | 9.9915±0.2 mas[2] |
| Distance | 326 ± 7 ly (100 ± 2 pc) |
| Absolute magnitude (MV) | −0.77[1] |
| Details | |
| Mass | 2±0.3[7] M☉ |
| Radius | 116±9[7] R☉ |
| Luminosity | 1,738[2] L☉ |
| Surface gravity (log g) | 0.6±0.02[7] cgs |
| Temperature | 3,470±125[7] K |
| Other designations | |
| ε Mus, CD−67 1216, CPD−67 1931, HD 106849, HIP 59929, HR 4671, SAO 251830 | |
| Database references | |
| SIMBAD | data |
Originally a main-sequence star of around 2 solar masses,[7] Epsilon Muscae is now on the asymptotic giant branch[4] and has expanded to 117 times the Sun's diameter and 1,700 its luminosity.[7] It is a semiregular variable, varying between visual magnitudes 4.0 and 4.3[3] in eight distinct periods ranging from a month to over half a year in length.[5] Its distance from the Earth is about the same as the Lower Centaurus–Crux subgroup of the Scorpius–Centaurus association, although it is moving much faster at around 100 km/s and does not share a common origin.[9]