Alpha Sextantis

α Sextantis
Location of α Sextantis on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 10h 07m 56.29556s[1]
Declination −0° 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]
Distance280 ± 20 ly
(87 ± 7 pc)
Absolute magnitude (MV)−0.29±0.21[5]
Details
Mass2.57±0.32[6] M☉
Radius3.07[6] R☉
Luminosity90[6] L☉
Surface gravity (log g)3.55[7] cgs
Temperature9,984[8] K
Metallicity [Fe/H]−0.03±0.18[7] dex
Rotational velocity (v sin i)21[9] km/s
Age385[6] Myr
Other designations
α Sex, 15 Sextantis, BD+00°2615, FK5 2814, HD 87887, HIP 49641, HR 3981, SAO 137366.[10]
Database references
SIMBADdata

Alpha Sextantis (α Sex, α Sextantis) is the brightest star in the equatorial constellation of Sextans.[11] It is visible to the naked eye on a dark night with an apparent visual magnitude of 4.49.[2] The distance to this star, as determined from parallax measurements,[1] is around 280 light years. This is considered an informal "equator star", as it lies less than a quarter of a degree south of the celestial equator. In 1900, it was 7 minutes of arc north of the equator. As a result of a shift in the Earth's axial tilt, it crossed over to the southern 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 with a period of 9.1 hours.[6]

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

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Gerbaldi1999 was invoked but never defined (see the help page).
  6. ^ a b c d e f g h i Cite error: The named reference Bowman was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Pintado2003 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Royer2002 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Darling was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kaler was invoked but never defined (see the help page).
  13. ^ "VSX : Detail for alf Sex". www.aavso.org. Retrieved 2023-12-02.