Article · Wikipedia archive · Last revised Jun 8, 2026

Beta Sextantis

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 8.89 mas, is around 367 light years.

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Jun 8, 2026
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Wikipedia ↗
β Sextantis
Location of β Sextantis (circled in red)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 10h 30m 17.48029s1
Declination −00° 38′ 13.3145″1
Apparent magnitude (V) 5.072
Characteristics
Evolutionary stage Main sequence3
Spectral type B6 V4 or B5 IV/V5
U−B color index −0.512
B−V color index −0.142
Variable type α2 CVn6
Astrometry
Radial velocity (Rv)11.6±2.87 km/s
Proper motion (μ) RA: −39.290 mas/yr1
Dec.: −23.582 mas/yr1
Parallax (π)8.8899±0.1477 mas1
Distance367 ± 6 ly
(112 ± 2 pc)
Absolute magnitude (MV)−0.388
Details
Mass4.01±0.073 M☉
Radius3.009 R☉
Luminosity3303 L☉
Surface gravity (log g)4.2110 cgs
Temperature13,8703 K
Metallicity [Fe/H]0.1910 dex
Rotational velocity (v sin i)85±410 km/s
Age21611 Myr
Other designations
β Sex, 30 Sextantis, BD+00°2663, FK5 2841, HD 90994, HIP 51437, HR 4119, SAO 13760812
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 5.07,2 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.

A light curve for Beta Sextantis, plotted from TESS data,13 source ↗

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 variable6 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.104

References

References

  1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. Crawford, D. L.; et al. (1971). "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere". The Astronomical Journal. 76: 1058. Bibcode:1971AJ.....76.1058C. doi:10.1086/111220.
  3. Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  4. Mathys, G.; et al. (March 1986). "Photometric variability of some early-type stars". Astronomy and Astrophysics Supplement Series. 63 (3): 403–416. Bibcode:1986A&AS...63..403M.
  5. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode:1999MSS...C05....0H.
  6. Kholopov, P. N.; et al. (April 1989). "The 69th Name-List of Variable Stars". Information Bulletin on Variable Stars. 3323 (3323): 1. Bibcode:1989IBVS.3323....1K.
  7. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012). "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project". Astronomy & Astrophysics. 546: 14. arXiv:1208.3048. Bibcode:2012A&A...546A..61D. doi:10.1051/0004-6361/201219219. S2CID 59451347. A61.
  8. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  9. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017-10-01). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471: 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. ISSN 0035-8711.
  10. Hempel, M.; Holweger, H. (September 2003). "Abundance analysis of late B stars. Evidence for diffusion and against weak stellar winds". Astronomy and Astrophysics. 408 (3): 1065–1076. Bibcode:2003A&A...408.1065H. doi:10.1051/0004-6361:20030889.
  11. Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031.
  12. "bet Sex". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-13.
  13. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 27 August 2024.