63 Ophiuchi

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63 Ophiuchi
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Cercle rouge 100%.svg
The location of 63 Ophiuchi (circled) in the constellation Sagittarius
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 17h 54m 54.04380s[1]
Declination −24° 53′ 13.5413″[1]
Apparent magnitude (V) 6.20[2]
Spectral type O8II((f))[3]
U−B color index –0.89[4]
B−V color index +0.04[4]
Radial velocity (Rv)–11[5] km/s
Proper motion (μ) RA: 1.66[1] mas/yr
Dec.: –2.63[1] mas/yr
Parallax (π)−0.77 ± 0.40[1] mas
Absolute magnitude (MV)−6.0[6]
Surface gravity (log g)3.5[7] cgs
Temperature34,000[7] K
Rotational velocity (v sin i)35[7]-86[8] km/s
Other designations
63 Oph, CD−24° 13615, HD 162978, HIP 87706, HR 6672, SAO 185928
Database references

63 Ophiuchi is an O-type giant star in the constellation Sagittarius, despite its name. During a 2009 survey for companions of massive stars, it was observed using speckle interferometry but no companion was found.[9] Uncertain negative parallax measurements of –0.77 ± 0.40 mas suggest that this extremely luminous star may be located about 4000 light-years away. An estimate of the distance based on the strength of the Ca II line yields a more modest value of 2,605 ly (799 pc).[10] The star lies only 0.3° north of the galactic plane.

In 1983, astronomers from the Sternberg Astronomical Institute in Moscow, Russia identified a faint, shell-shaped nebula surrounding the star that was being excited by the star's energy. Named Sharpless 22, this ring-shaped nebula has a double-shell structure with an inner envelope spanning 45–50 (9–18 pc), surrounded by a diffuse envelope some 65–80′ (14–29 pc) across. At an estimated mass loss rate of (6–8) × 10−6 M/yr, it would take the star about (1–5) × 105 years to produce such a nebula from the outflow of its stellar wind.[11]


  1. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
  2. ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J. (2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement. 211: 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10.
  4. ^ a b Schild, R. E.; et al. (April 1983), "UBV photometry for southern OB stars", Astrophysical Journal Supplement Series, 51: 321–336, Bibcode:1983ApJS...51..321S, doi:10.1086/190852
  5. ^ Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Washington, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W
  6. ^ Schröder, S. E.; Kaper, L.; Lamers, H. J. G. L. M.; Brown, A. G. A. (2004). "On the Hipparcos parallaxes of O stars". Astronomy and Astrophysics. 428: 149. arXiv:astro-ph/0408370. Bibcode:2004A&A...428..149S. doi:10.1051/0004-6361:20047185.
  7. ^ a b c Martins, F.; Hervé, A.; Bouret, J.-C.; Marcolino, W.; Wade, G. A.; Neiner, C.; Alecian, E.; Grunhut, J.; Petit, V. (2015). "The MiMeS survey of magnetism in massive stars: CNO surface abundances of Galactic O stars". Astronomy & Astrophysics. 575: A34. arXiv:1411.4420. Bibcode:2015A&A...575A..34M. doi:10.1051/0004-6361/201425173.
  8. ^ Hubrig, S.; et al. (November 2008), "Magnetic field measurements of O stars with FORS 1 at the VLT", Astronomy and Astrophysics, 490 (2): 793–800, arXiv:0808.2039, Bibcode:2008A&A...490..793H, doi:10.1051/0004-6361:200810171
  9. ^ Mason, Brian D.; et al. (February 2009), "The High Angular Resolution Multiplicity of Massive Stars", The Astronomical Journal, 137 (2): 3358–3377, arXiv:0811.0492, Bibcode:2009AJ....137.3358M, doi:10.1088/0004-6256/137/2/3358
  10. ^ Megier, A.; et al. (November 2009), "The interstellar Ca II distance scale", Astronomy and Astrophysics, 507 (2): 833–840, Bibcode:2009A&A...507..833M, doi:10.1051/0004-6361/20079144
  11. ^ Lozinskaya, T. A.; et al. (June 1983), "A New Search for Ring Nebulae around Of-Stars - SHARPLESS22", Soviet Astronomy Letters, 9 (6): 344–345, Bibcode:1983SvAL....9..344L