R Muscae
R Muscae is a yellow-white hued variable star in the southern constellation of Musca. It has a nominal apparent visual magnitude of 6.31, which is near the lower limit of visibility to the naked eye. The distance to this star, as determined from its annual parallax shift of 1.00 mas, is around 3,260 light years.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Musca |
| Right ascension | 12h 42m 05.02561s |
| Declination | −69° 24′ 27.1966″ |
| Apparent magnitude (V) | 5.93 - 6.73 |
| Characteristics | |
| Spectral type | F7 Ib - G2 |
| B−V color index | 0.750±0.020 |
| Variable type | δ Cep |
| Astrometry | |
| Radial velocity (Rv) | +3.8±2.9 km/s |
| Proper motion (μ) | RA: −4.180 mas/yr Dec.: −2.127 mas/yr |
| Parallax (π) | 1.0002 ± 0.0291 mas |
| Distance | 3,260 ± 90 ly (1,000 ± 30 pc) |
| Absolute magnitude (MV) | -3.62 |
| Details | |
| Radius | 65 R☉ |
| Luminosity | 2,541 L☉ |
| Surface gravity (log g) | 2.0±0.1 cgs |
| Temperature | 5,985±54 K |
| Metallicity [Fe/H] | +0.10±0.05 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an F-type supergiant star with a baseline stellar classification of F7 Ib. It is a Classical Cepheid variable ranging from apparent magnitude 5.93 to 6.73 over 7.51 days, while varying between spectral types F7 Ib and G2. The star was suspected of having a detectable companion, but this finding was later disputed. Gaia and HST observations have shown that there is a companion, a 15th-magnitude star 7″ away. There is an X-ray source with a luminosity of 6.3×1029 erg s−1 located at an angular separation of 1.9″ from R Muscae.