Alpha Sculptoris

Alpha Sculptoris

Alpha Sculptoris
Diagram showing star positions and boundaries of the Sculptor constellation and its surroundings

Location of α Sculptoris (circled) near the center
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sculptor
Right ascension 00h 58m 36.35930s[1]
Declination −29° 21′ 26.8247″[1]
Apparent magnitude (V) +4.30[2]
Spectral type B7 IIIp[3]
U−B color index −0.515[4]
B−V color index −0.155[4]
Radial velocity (Rv) +10.2[2] km/s
Proper motion (μ) RA: +20.13[1] mas/yr
Dec.: +5.31[1] mas/yr
Parallax (π) 4.20 ± 0.18[1] mas
Distance 780 ± 30 ly
(240 ± 10 pc)
Surface gravity (log g) 3.60[5] cgs
Temperature 17,379[5] K
Metallicity [Fe/H] 0.90[5] dex
Rotational velocity (v sin i) 20[6] km/s
Other designations
CD–30 297, FK5 35, HD 5737, HIP 4577, HR 280, SAO 166716.[7]

Alpha Sculptoris (α Scl, α Sculptoris) is the Bayer designation for a star in the southern constellation of Sculptor. It has an apparent visual magnitude of +4.30,[2] which makes it the brightest star in this generally faint constellation. Parallax measurements collected during the Hipparcos mission provide a distance estimate for this star, placing it at roughly 780 light-years (240 parsecs), with a 4% margin of error.[1]

Alpha Sculptoris is a blue-white B-type giant. It is classified as an SX Arietis type variable star and its magnitude varies by 0.01.

The luminosity of α Scl is around 1700 times that of the Sun while its surface temperature is 14,000 kelvins. The radius of Alpha Sculptoris is calculated to be 7 times solar while its mass is 5.5 times that of our own star. Spectral variations observed in this star where once believed to be caused by an orbiting black hole but are now known to be the result of chemical variations in its atmosphere.


  1. ^ a b c d e f van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664.  
  2. ^ a b c Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg,  
  3. ^ Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan,  
  4. ^ a b Gutierrez-Moreno, Adelina; et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17,  
  5. ^ a b c Schmitt, A. (March 1973), "The weak-helium-line star α Sculptoris. I. The line-spectrum", Astronomy and Astrophysics Supplement 9: 427,  
  6. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365,  
  7. ^ "alf Scl -- Rotationally variable Star", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-04-08 

External links

  • Alpha Scl