Chi Scorpii

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χ Scorpii
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 16h 13m 50.90563s[1]
Declination −11° 50′ 15.8891″[1]
Apparent magnitude (V) 5.22[2]
Spectral type K3 III[3]
U−B color index +1.54[2]
B−V color index +1.42[2]
Radial velocity (Rv)−23.61[4] km/s
Proper motion (μ) RA: −4.82[1] mas/yr
Dec.: −10.20[1] mas/yr
Parallax (π)8.62 ± 0.35[1] mas
Distance380 ± 20 ly
(116 ± 5 pc)
Absolute magnitude (MV)−0.08[5]
Mass1.09±0.15[6] M
Radius26.76±0.75[6] R
Luminosity190.9±10.5[6] L
Surface gravity (log g)1.66±0.05[6] cgs
Temperature4,151±13[6] K
Metallicity [Fe/H]−0.01±0.10[6] dex
Rotational velocity (v sin i)8[7] km/s
Age8.39±2.64[6] Gyr
Other designations
17 Scorpii, GC 21828, HD 145897, HIP 79540, HR 6048, SAO 159793, BD-11° 4096[8]
Database references

Chi Scorpii (χ Sco, χ Scorpii) is a star in the zodiac constellation of Scorpius. It can be faintly seen with the naked eye and has an apparent visual magnitude of 5.22.[2] Based upon parallax measurements, this star is around 380 light years from the Sun.

This is an orange-hued K-type giant star with a stellar classification of K3 III.[3] There is a 57% chance that this evolved star is on the horizontal branch and a 43% chance it is still on the red-giant branch. If it is on the former, the star is estimated to have 1.09 times the mass of the Sun, nearly 27 times the solar radius and shines with 191 times the Sun's luminosity. It is around 8 billion years old.[6]


  1. ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, Bibcode:1986EgUBV........0M. 
  3. ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H. 
  4. ^ Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477Freely accessible, Bibcode:2002ApJS..141..503N, doi:10.1086/340570. 
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  6. ^ a b c d e f g h Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy & Astrophysics, 574: A116, arXiv:1412.4634Freely accessible, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360. Values are for the slightly higher probability horizontal branch model fit. 
  7. ^ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B. 
  8. ^ "chi Sco -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-09-24. 

External links[edit]

  • Kaler, James B. (August 12, 2016), "Chi and Psi Scorpii", Stars, University of Illinois, retrieved 2016-09-25.