S Muscae
Star in the constellation Musca
From Wikipedia, the free encyclopedia
S Muscae is a classical (δ) Cepheid variable star in the constellation Musca about 2,600 light years away.
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Musca |
| Right ascension | 12h 12m 47.01834s[1] |
| Declination | −70° 09′ 06.4363″[1] |
| Apparent magnitude (V) | 6.394[2] (5.89 - 6.49[3]) |
| Characteristics | |
| Spectral type | F6Ib (F6-G0[3]) + B5V[4] |
| U−B color index | +0.66[5] |
| B−V color index | +1.00[5] |
| Variable type | δ Cepheid[3] |
| Astrometry | |
| Radial velocity (Rv) | −1.91[6] km/s |
| Proper motion (μ) | RA: −7.79[1] mas/yr Dec.: −0.60[1] mas/yr |
| Parallax (π) | 1.99±0.84 mas[1] |
| Distance | 863[2] pc |
| Absolute magnitude (MV) | −4.01[7] |
| Orbit[7][8] | |
| Period (P) | 504.9±0.07 |
| Semi-major axis (a) | 794 AU |
| Eccentricity (e) | 0.08±0.002 |
| Inclination (i) | 32±1° |
| Semi-amplitude (K1) (primary) | 14.7±0.2 km/s |
| Details | |
| Mass | 6.2[7] M☉ |
| Radius | 65.1[2] R☉ |
| Luminosity | 3,467[7] L☉ |
| Metallicity | +0.18[9] |
| companion | |
| Mass | 5.3[7] M☉ |
| Temperature | 17,000[10] K |
| Other designations | |
| S Mus, HR 4645, SAO 251791, CD−69°977, GSC 09231-00752, HD 106111, GC 16679, HIP 59551, AAVSO 1207-69 | |
| Database references | |
| SIMBAD | data |
S Muscae is a yellow supergiant ranging between spectral types F6Ib and G0Ib and magnitudes 5.89 to 6.49 over a period of 9.66 days.[3] It is a luminous star around six times as massive as the Sun and 65.1 times the radius of the Sun. It is a binary star with a blue-white main sequence star companion likely to be of spectral type B3V to B5V with a mass of just over five solar masses,[12] one of the hottest and brightest companions of a Cepheid known. The two stars orbit each other every 505 days.[13]
S Muscae has been found to lie within the faint star cluster ASCC 69.[14]