Beta Sextantis
Star in the constellation Sextans
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Beta Sextantis, Latinized from β Sextantis, is a variable star in the equatorial constellation of Sextans. With an apparent visual magnitude of 5.07,[2] it is faintly visible to the naked eye on a dark night. According to the Bortle scale, it can be viewed from brighter lit suburban skies. The distance to this star, based upon an annual parallax shift of 8.89 mas,[1] is around 367 light years.
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sextans |
| Right ascension | 10h 30m 17.48029s[1] |
| Declination | −00° 38′ 13.3145″[1] |
| Apparent magnitude (V) | 5.07[2] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | B6 V[4] or B5 IV/V[5] |
| U−B color index | −0.51[2] |
| B−V color index | −0.14[2] |
| Variable type | α2 CVn[6] |
| Astrometry | |
| Radial velocity (Rv) | 11.6±2.8[7] km/s |
| Proper motion (μ) | RA: −39.290 mas/yr[1] Dec.: −23.582 mas/yr[1] |
| Parallax (π) | 8.8899±0.1477 mas[1] |
| Distance | 367 ± 6 ly (112 ± 2 pc) |
| Absolute magnitude (MV) | −0.38[8] |
| Details | |
| Mass | 4.01±0.07[3] M☉ |
| Radius | 3.00[9] R☉ |
| Luminosity | 330[3] L☉ |
| Surface gravity (log g) | 4.21[10] cgs |
| Temperature | 13,870[3] K |
| Metallicity [Fe/H] | 0.19[10] dex |
| Rotational velocity (v sin i) | 85±4[10] km/s |
| Age | 216[11] Myr |
| Other designations | |
| β Sex, 30 Sextantis, BD+00°2663, FK5 2841, HD 90994, HIP 51437, HR 4119, SAO 137608[12] | |
| Database references | |
| SIMBAD | data |
This star served as a primary standard in the MK spectral classification system with a stellar classification of B6 V,[4] indicating that it is a B-type main sequence star. However, Houk and Swift (1999) list a classification of B5 IV/V, suggesting it may be transitioning into a subgiant star.[5] Stellar evolution models support this is a main sequence star.[3] It has served as a uvby photometric standard, but is also categorized as an Alpha2 Canum Venaticorum variable[6] with a suspected period of 15.4 days. This lengthy a period conflicts with a relatively high projected rotational velocity of 85 km/s, leaving the explanation for the variance unresolved.[10][4]