# Alpha Sextantis

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Star in the constellation Sextans

α Sextantis Location of α Sextantis on the map (circled) Observation data Epoch J2000 Equinox J2000 Constellation Sextans Right ascension 10h 07m 56.29556s[1] Declination −00° 22′ 17.8621″[1] Apparent magnitude (V) 4.49[2] Characteristics Spectral type A0 III[3] U−B color index −0.07[2] B−V color index −0.04[2] Astrometry Radial velocity (Rv) 10.00[4] km/s Proper motion (μ) RA: −25.83[1] mas/yr Dec.: −4.25[1] mas/yr Parallax (π) 11.51±0.98 mas[1] Distance 280 ± 20 ly (87 ± 7 pc) Absolute magnitude (MV) −0.29±0.21[5] Details Mass 2.57±0.32[6] M☉ Radius 3.07[6] R☉ Luminosity 90[6] L☉ Surface gravity (log g) 3.55[7] cgs Temperature 9,984[8] K Metallicity [Fe/H] −0.03±0.18[7] dex Rotational velocity (v sin i) 21[9] km/s Age 385[6] Myr Other designations α Sex, 15 Sextantis, BD+00°2615, FK5 2814, HD 87887, HIP 49641, HR 3981, SAO 137366.[10] Database references SIMBAD data

**Alpha Sextantis** (α Sex, α Sextantis) is the brightest [star](/source/Star) in the equatorial [constellation](/source/Constellation) of [Sextans](/source/Sextans).[11] It is visible to the naked eye on a dark night with an [apparent visual magnitude](/source/Apparent_visual_magnitude) of 4.49.[2] The distance to this star, as determined from [parallax](/source/Stellar_parallax) measurements,[1] is around 280 [light years](/source/Light_year). This is considered an informal "equator star", as it lies less than a quarter of a [degree](/source/Degree_(angle)) south of the [celestial equator](/source/Celestial_equator). In 1900, it was 7 [minutes of arc](/source/Minute_of_arc) north of the [equator](/source/Equator). As a result of Earth's [axial precession](/source/Axial_precession), it crossed over to the [southern hemisphere](/source/Southern_celestial_hemisphere) in December 1923.[12]

The variability of Alpha Sextantis was discovered by Aven Magded Hamadamen and included in the International Variable Star Index.[13] The star undergoes [pulsations](/source/Stellar_pulsation) with a period of 9.1 hours.[6]

This is an [evolved](/source/Stellar_evolution) [A-type](/source/A-type_star) [giant star](/source/Giant_star) with a [stellar classification](/source/Stellar_classification) of A0 III.[3] It has around 2.5[6] times the [mass of the Sun](/source/Solar_mass) and three[6] times the [Sun's radius](/source/Solar_radius). The abundance of elements is similar to that in the Sun, but with a large uncertainty.[7] It radiates 90 times the [solar luminosity](/source/Solar_luminosity)[6] from its [outer atmosphere](/source/Stellar_atmosphere) at an [effective temperature](/source/Effective_temperature) of 9,984 K.[8] Alpha Sextantis is nearing the end of its life as a [main-sequence star](/source/Main-sequence_star); it is around 385[6] million years old with a [projected rotational velocity](/source/Projected_rotational_velocity) of 21 km/s.[9]

## References

1. ^ [***a***](#cite_ref-vanLeeuwen2007_1-0) [***b***](#cite_ref-vanLeeuwen2007_1-1) [***c***](#cite_ref-vanLeeuwen2007_1-2) [***d***](#cite_ref-vanLeeuwen2007_1-3) [***e***](#cite_ref-vanLeeuwen2007_1-4) [***f***](#cite_ref-vanLeeuwen2007_1-5) van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", *Astronomy and Astrophysics*, **474** (2): 653–664, [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752), [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357), [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600).

1. ^ [***a***](#cite_ref-Mermilliod1986_2-0) [***b***](#cite_ref-Mermilliod1986_2-1) [***c***](#cite_ref-Mermilliod1986_2-2) [***d***](#cite_ref-Mermilliod1986_2-3) Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", *Catalogue of Eggen's UBV Data*, [SIMBAD](/source/SIMBAD), [Bibcode](/source/Bibcode_(identifier)):[1986EgUBV........0M](https://ui.adsabs.harvard.edu/abs/1986EgUBV........0M).

1. ^ [***a***](#cite_ref-Cowley1969_3-0) [***b***](#cite_ref-Cowley1969_3-1) Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", *Astronomical Journal*, **74**: 375–406, [Bibcode](/source/Bibcode_(identifier)):[1969AJ.....74..375C](https://ui.adsabs.harvard.edu/abs/1969AJ.....74..375C), [doi](/source/Doi_(identifier)):[10.1086/110819](https://doi.org/10.1086%2F110819).

1. **[^](#cite_ref-Gontcharov2006_4-0)** Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". *Astronomy Letters*. **32** (11): 759–771. [arXiv](/source/ArXiv_(identifier)):[1606.08053](https://arxiv.org/abs/1606.08053). [Bibcode](/source/Bibcode_(identifier)):[2006AstL...32..759G](https://ui.adsabs.harvard.edu/abs/2006AstL...32..759G). [doi](/source/Doi_(identifier)):[10.1134/S1063773706110065](https://doi.org/10.1134%2FS1063773706110065). [S2CID](/source/S2CID_(identifier)) [119231169](https://api.semanticscholar.org/CorpusID:119231169).

1. **[^](#cite_ref-Gerbaldi1999_5-0)** Gerbaldi, M.; et al. (June 1999), "Search for reference A0 dwarf stars: Masses and luminosities revisited with HIPPARCOS parallaxes", *Astronomy and Astrophysics Supplement*, **137** (2): 273–292, [Bibcode](/source/Bibcode_(identifier)):[1999A&AS..137..273G](https://ui.adsabs.harvard.edu/abs/1999A&AS..137..273G), [doi](/source/Doi_(identifier)):[10.1051/aas:1999248](https://doi.org/10.1051%2Faas%3A1999248).

1. ^ [***a***](#cite_ref-Bowman_6-0) [***b***](#cite_ref-Bowman_6-1) [***c***](#cite_ref-Bowman_6-2) [***d***](#cite_ref-Bowman_6-3) [***e***](#cite_ref-Bowman_6-4) [***f***](#cite_ref-Bowman_6-5) [***g***](#cite_ref-Bowman_6-6) [***h***](#cite_ref-Bowman_6-7) [***i***](#cite_ref-Bowman_6-8) Monier, Richard; Bowman, Dominic M.; Lebreton, Yveline; Deal, Morgan (2023). ["The Unexpected Optical and Ultraviolet Variability of the Standard Star α Sex (HD 87887)"](https://doi.org/10.3847%2F1538-3881%2Facdee4). *The Astronomical Journal*. **166** (2): 73. [arXiv](/source/ArXiv_(identifier)):[2306.08551](https://arxiv.org/abs/2306.08551). [Bibcode](/source/Bibcode_(identifier)):[2023AJ....166...73M](https://ui.adsabs.harvard.edu/abs/2023AJ....166...73M). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/acdee4](https://doi.org/10.3847%2F1538-3881%2Facdee4).

1. ^ [***a***](#cite_ref-Pintado2003_7-0) [***b***](#cite_ref-Pintado2003_7-1) [***c***](#cite_ref-Pintado2003_7-2) Pintado, O. I.; Adelman, S. J. (August 2003), "Elemental abundance analyses with the EBASIM spectrograph of the 2.1-m CASLEO Observatory Telescope. I. The late B and early A stars vec xi Octantis, alpha Sextantis, and 68 Tauri", *Astronomy and Astrophysics*, **406** (3): 987–994, [Bibcode](/source/Bibcode_(identifier)):[2003A&A...406..987P](https://ui.adsabs.harvard.edu/abs/2003A&A...406..987P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20030813](https://doi.org/10.1051%2F0004-6361%3A20030813).

1. ^ [***a***](#cite_ref-Mcdonald2012_8-0) [***b***](#cite_ref-Mcdonald2012_8-1) McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", *Monthly Notices of the Royal Astronomical Society*, **427** (1): 343–57, [arXiv](/source/ArXiv_(identifier)):[1208.2037](https://arxiv.org/abs/1208.2037), [Bibcode](/source/Bibcode_(identifier)):[2012MNRAS.427..343M](https://ui.adsabs.harvard.edu/abs/2012MNRAS.427..343M), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2012.21873.x](https://doi.org/10.1111%2Fj.1365-2966.2012.21873.x), [S2CID](/source/S2CID_(identifier)) [118665352](https://api.semanticscholar.org/CorpusID:118665352).

1. ^ [***a***](#cite_ref-Royer2002_9-0) [***b***](#cite_ref-Royer2002_9-1) Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", *Astronomy and Astrophysics*, **393** (3): 897–911, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0205255](https://arxiv.org/abs/astro-ph/0205255), [Bibcode](/source/Bibcode_(identifier)):[2002A&A...393..897R](https://ui.adsabs.harvard.edu/abs/2002A&A...393..897R), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20020943](https://doi.org/10.1051%2F0004-6361%3A20020943), [S2CID](/source/S2CID_(identifier)) [14070763](https://api.semanticscholar.org/CorpusID:14070763).

1. **[^](#cite_ref-SIMBAD_10-0)** ["alf Sex"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=alf+Sex). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2016-12-12.

1. **[^](#cite_ref-Darling_11-0)** ["Sextans (abbr. Sex, gen. Sextantis)"](http://www.daviddarling.info/encyclopedia/S/Sex.html), *The Internet Encyclopedia of Science*, retrieved 2016-12-12.

1. **[^](#cite_ref-Kaler_12-0)** Kaler, James B., ["Alpha Sextantis"](http://stars.astro.illinois.edu/sow/alphasext.html), *Stars*, [University of Illinois](/source/University_of_Illinois), retrieved 2016-12-12.

1. **[^](#cite_ref-13)** ["VSX : Detail for alf Sex"](https://www.aavso.org/vsx/index.php?view=detail.top&oid=2227107). *www.aavso.org*. Retrieved 2023-12-02.

## External links

- [Astronomy Knowledge Database](https://web.archive.org/web/20060705214728/http://www.site.uottawa.ca:4321/astronomy/index.html#AlphaSextantis)

v t e Constellation of Sextans COSMOS field List of stars in Sextans Sextans in Chinese astronomy Stars Bayer α β γ δ ε Flamsteed 7 18 19 23 24 25 35 41 Variable Y UY HR 3879 3915 4092 4233 HD 86081 (Bibhā) 92788 93396 Other BD−08°2823 Gliese 393 K2-239 LHS 292 PSR J0952−0607 TOI-561 WASP-43 (Gnomon) WASP-127 Exoplanets BD−08°2823 b c HD 86081 b (Santamasa) HD 92788 b KELT-11b TOI-561 b WASP-43b (Astrolábos) Galaxies NGC 2967 2974 2980 3007 3015 3018 3044 3110 3115 3156 3166 3169 3326 3341 3423 Other 3MM-1 AzTECC71 Baby Boom Galaxy CAPERS-LRD-z9 CID-42 CID-346 Cosmos Redshift 7 HD1 Infinity Galaxy J1000+0221 J1010+0612 J10405643–0103584 LAE J095950.99+021219.1 LBQS 1009−0252 MoM-z14 PG 1011−040 PG 1012+008 PGC 29820 PGC 3092152 PMN J0948+0022 REBELS-25 Sextans A Sextans B Sextans Dwarf Spheroidal Zhúlóng Galaxy clusters Abell 907 CL J1001+0220 Hyperion proto-supercluster Astronomical events AT 2018hyz SN 1000+0216 Category

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Adapted from the Wikipedia article [Alpha Sextantis](https://en.wikipedia.org/wiki/Alpha_Sextantis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Alpha_Sextantis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.