13 Scorpii

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13 Scorpii
Observation data
Epoch J2000      Equinox J2000
Constellation Scorpius
Right ascension 16h 12m 18.20490s[1]
Declination −27° 55′ 34.9457″[1]
Apparent magnitude (V) +4.568[2]
Spectral type B2V[3]
U−B color index −0.74[4]
B−V color index −0.16[4]
Radial velocity (Rv) 0 ± 5[5] km/s
Proper motion (μ) RA: −10.38[1] mas/yr
Dec.: −23.94[1] mas/yr
Parallax (π) 6.81 ± 0.16[1] mas
Distance 480 ± 10 ly
(147 ± 3 pc)
Period (P) 5.7805 d
Eccentricity (e) 0.19
Periastron epoch (T) JD 2443298.40
Argument of periastron (ω)
Semi-amplitude (K1)
31.5 km/s
13 Sco A
Mass 7.80[6] M
Luminosity 3020[7] L
Temperature 24000[7] K
Rotational velocity (v sin i) 165[8] km/s
Age 11[6] Myr
13 Sco B
Mass 1.12[6] M
Other designations
c2 Sco, 13 Sco, CD−27° 10841, HD 145482, HIP 79404, HR 6028, SAO 184221[9]
Database references

13 Scorpii, also known by its Bayer designation c2 Scorpii, is a binary star in the constellation Scorpius. Its apparent magnitude is 4.57,[2] meaning it can be faintly seen with the naked eye. Based on parallax estimates made by the Hipparcos spacecraft, the system is located about 480 light-years (147 parsecs) away.[1] It is located within the Upper Scorpius subgroup of the Scorpius–Centaurus Association.[6]

13 Scorpii is a spectroscopic binary, meaning the two stars are too close to be individually resolved, but periodic Doppler shifts in the star's spectrum indicate there must be orbital motion. In this case, light from only one of its stars can be detected and it is a double-lined spectroscopic binary,[3] the two have an orbital period of 5.7805 days and an eccentricity of 0.19.[3] The primary star, at 11 million years old,[6] is an B-type main-sequence star with a spectral type of B2V.[3] While the primary's mass is estimated to be about 7.8 M, its companion is thought to have a mass of 1.12 M.[6]


  1. ^ a b c d e f van Leeuwen, F.; et al. (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 Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. 
  3. ^ a b c d e Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727. arXiv:astro-ph/0406573Freely accessible. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. 
  4. ^ a b Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4. Bibcode:1966CoLPL...4...99J. 
  5. ^ Evans, D. S. (2006). "The Revision of the General Catalogue of Radial Velocities". Bibcode:1967IAUS...30...57E. 
  6. ^ a b c d e f Bonavita, M.; et al. (2016). "SPOTS: The Search for Planets Orbiting Two Stars. II. First constraints on the frequency of sub-stellar companions on wide circumbinary orbits". Astronomy & Astrophysics. 593. arXiv:1605.03962Freely accessible. Bibcode:2016A&A...593A..38B. doi:10.1051/0004-6361/201628231. 
  7. ^ a b Hernández, J.; Calvet, N.; Hartmann, L.; Briceño, C.; Sicilia-Aguilar, A.; Berlind, P. (2005). "Herbig Ae/Be Stars in nearby OB Associations". The Astronomical Journal. 129 (2): 856–871. arXiv:astro-ph/0410494Freely accessible. Bibcode:2005AJ....129..856H. doi:10.1086/426918. 
  8. ^ Strom, S. E.; Wolff, S. C.; Dror, D. H. A. (2005). "B Star Rotational Velocities in h and χ Persei: A Probe of Initial Conditions during the Star Formation Epoch?". The Astronomical Journal. 129 (2): 809–828. arXiv:astro-ph/0410337Freely accessible. Bibcode:2005AJ....129..809S. doi:10.1086/426748. 
  9. ^ "* c02 Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 April 2017.