Sigma Serpentis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 16h 22m 04.34822s |
| Declination | +01° 01′ 44.5566″ |
| Apparent magnitude (V) | +4.82 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | F3 V |
| U−B color index | +0.025 |
| B−V color index | +0.338 |
| Astrometry | |
| Radial velocity (Rv) | −49.3±0.9 km/s |
| Proper motion (μ) | RA: −158.172 mas/yr Dec.: +50.612 mas/yr |
| Parallax (π) | 35.5388±0.1366 mas |
| Distance | 91.8 ± 0.4 ly (28.1 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.63 |
| Details | |
| Mass | 1.54 M☉ |
| Radius | 1.81 R☉ |
| Luminosity | 7.2 L☉ |
| Surface gravity (log g) | 4.11 cgs |
| Temperature | 7,009 K |
| Metallicity [Fe/H] | −0.01 dex |
| Rotational velocity (v sin i) | 77.7 km/s |
| Age | 1.15±0.10 Gyr |
| Other designations | |
| σ Ser, 50 Serpentis, BD+01°3215, FK5 1427, HD 147449, HIP 80179, HR 6093, SAO 121540 | |
| Database references | |
| SIMBAD | data |
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. 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.
Barry (1970) assigned this star a stellar classification of F3 V, indicating an ordinary F-type main-sequence star. It is about one billion years old and is spinning with a projected rotational velocity of 77.7 km/s. 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.
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. Gaia DR3 astrometry confirms a similar parallax and proper motion.