Beta Sextantis

β Sextantis

A light curve for Beta Sextantis, plotted from TESS data,
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 10h 30m 17.48s
Declination −00° 38 13.3
Apparent magnitude (V) 5.07
Characteristics
Evolutionary stage main sequence
Spectral type B6 V or B5 IV/V
U−B color index −0.51
B−V color index −0.14
Variable type α2 CVn
Astrometry
Radial velocity (Rv)11.6±2.8 km/s
Proper motion (μ) RA: −38.805 mas/yr
Dec.: −24.290 mas/yr
Parallax (π)8.9613±0.2448 mas
Distance364 ± 10 ly
(112 ± 3 pc)
Absolute magnitude (MV)−0.38
Details
Mass4.0 M
Radius3.2 R
Luminosity184 L
Surface gravity (log g)4.21 cgs
Temperature14,570 K
Metallicity [Fe/H]0.19 dex
Rotational velocity (v sin i)85±4 km/s
Age216 Myr
Other designations
β Sex, 30 Sextantis, BD+00°2663, FK5 2841, HD 90994, HIP 51437, HR 4119, SAO 137608
Database references
SIMBADdata

Beta Sextantis, Latinized from β Sextantis, is a variable star in the equatorial constellation of Sextans. With an apparent visual magnitude of 5.07, 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 8.96 mas, is around 364 light years.

This star served as a primary standard in the MK spectral classification system with a stellar classification of B6 V, 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. It has served as a uvby photometric standard, but is also categorized as an Alpha2 Canum Venaticorum variable 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.