Omega1 Scorpii

For other stars with this Bayer designation, see ω Scorpii
ω1 Scorpii
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Scorpius
Right ascension 16h 06m 48.42692s[1]
Declination −20° 40′ 09.0902″[1]
Apparent magnitude (V) +3.95[2]
Characteristics
Spectral type B1 V[2]
U−B color index −0.82
B−V color index −0.05[3]
Variable type Beta Cephei variable[4]
Astrometry
Radial velocity (Rv)−3.1[5] km/s
Proper motion (μ) RA: −8.98[1] mas/yr
Dec.: −23.48[1] mas/yr
Parallax (π)6.92 ± 0.26 mas[1]
Distance470 ± 20 ly
(145 ± 5 pc)
Absolute magnitude (MV)−1.87[6]
Details
Mass11.4[7] M☉
Radius6.6[8] R☉
Luminosity9,120[7] L☉
Temperature26,530[2] K
Metallicity [Fe/H]−0.45±0.15[9] dex
Rotation14.4 h[4]
Rotational velocity (v sin i)105[4] km/s
Age5[7] Myr
Other designations
Jabhat al Akrab,[10] ω1 Sco, 9 Scorpii, BD−20°4405, HD 144470, HIP 78933, HR 5993, SAO 184123[11]
Database references
SIMBADdata

ω1 Scorpii, Latinised as Omega1 Scorpii, is a star in the zodiac constellation of Scorpius. With an apparent visual magnitude of 3.95[2] it can be seen with the naked eye, 0.22 degree north of the ecliptic. Parallax measurements of this star give an estimated distance of around 470 light years from the Sun. It is a member of the Scorpius–Centaurus association.[12]

This is a B-type main sequence star with a stellar classification of B1 V.[2] It has a luminosity of 9,120 Suns, consistent with an isochronal age of 5 million years and an estimated mass of 11 solar masses.[7] The radius is about 6.6 times that of the Sun.[8] It has an effective temperature of 26,530 in its outer atmosphere.[2]

Omega1 Scorpii is a β Cephei star that undergoes non-radial pulsations at a rate of 15 cycles per day.[9] This is causing the surface temperature to fluctuate between 28,300 K and 22,600 K along the equator. The star is spinning rapidly with a projected rotational velocity of 105 km/s and an estimated rotation period of 14h.4. The poles of the star are inclined by around 60° to the line-of-sight from the Earth.[4]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Braganca2012 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Deutschman1976 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Berdyugina2003 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference rgcrv was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference Pecaut2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference cadars was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Daszkiewicz2005 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference allen1899 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Jilinski2006 was invoked but never defined (see the help page).