Sigma Serpentis
Star in the constellation Serpens
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Sigma Serpentis, Latinized from σ Serpentis, is a star in the equatorial constellation Serpens. It is faintly visible to the naked eye with an apparent visual magnitude of +4.82.[2] Based upon an annual parallax shift of 35.54 mas as seen from Earth, it is located 92 light-years from the Sun. The star is moving closer to the Sun with a radial velocity of −49 km/s.[5]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Serpens |
| Right ascension | 16h 22m 04.34822s[1] |
| Declination | +01° 01′ 44.5566″[1] |
| Apparent magnitude (V) | +4.82[2] |
| Characteristics | |
| Evolutionary stage | main sequence[1][3] |
| Spectral type | F3 V[4] |
| U−B color index | +0.025[2] |
| B−V color index | +0.338[2] |
| Astrometry | |
| Radial velocity (Rv) | −49.3±0.9[5] km/s |
| Proper motion (μ) | RA: −158.172 mas/yr[1] Dec.: +50.612 mas/yr[1] |
| Parallax (π) | 35.5388±0.1366 mas[1] |
| Distance | 91.8 ± 0.4 ly (28.1 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.63[6] |
| Details | |
| Mass | 1.54[7] M☉ |
| Radius | 1.81[7] R☉ |
| Luminosity | 7.2[7] L☉ |
| Surface gravity (log g) | 4.11[7] cgs |
| Temperature | 7,009[7] K |
| Metallicity [Fe/H] | −0.01[8] dex |
| Rotational velocity (v sin i) | 77.7[6] km/s |
| Age | 1.15±0.10[8] Gyr |
| Other designations | |
| σ Ser, 50 Serpentis, BD+01°3215, FK5 1427, HD 147449, HIP 80179, HR 6093, SAO 121540[9] | |
| Database references | |
| SIMBAD | data |
Barry (1970) assigned this star a stellar classification of F3 V,[4] indicating an ordinary F-type main-sequence star. It is about one billion years old[8] and is spinning with a projected rotational velocity of 77.7 km/s.[6] The star has an estimated 1.5 times the mass of the Sun and is radiating 7.2 times the Sun's luminosity from its photosphere at an effective temperature of 7,009 K.[7]
A candidate red dwarf companion star, of spectral type M2V, was identified in 2012 by Kevin Luhman and collaborators. It is 43″ from the primary, corresponding to a projected separation of 1200 AU.[10] Gaia DR3 astrometry confirms a similar parallax and proper motion.[11]