63 Ophiuchi

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] The small parallax measurement of 0.91±0.09 mas suggest that this extremely luminous star may be located about 3,600 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.

63 Ophiuchi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 17h 54m 54.04315s[1]
Declination −24° 53′ 13.5444″[1]
Apparent magnitude (V) 6.20[2]
Characteristics
Spectral type O8II((f))[3]
U−B color index –0.89[4]
B−V color index +0.04[4]
Astrometry
Radial velocity (Rv)–11[5] km/s
Proper motion (μ) RA: +0.704[1] mas/yr
Dec.: –2.194[1] mas/yr
Parallax (π)0.9071 ± 0.0882[1] mas
Distance3,600 ± 300 ly
(1,100 ± 100 pc)
Absolute magnitude (MV)−6.0[6]
Details
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
SIMBADdata

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]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  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 (1): 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528.
  4. 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: 149–157. arXiv:astro-ph/0408370. Bibcode:2004A&A...428..149S. doi:10.1051/0004-6361:20047185. S2CID 55115943.
  7. 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. S2CID 119258285.
  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, S2CID 16932907
  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, S2CID 119268845
  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
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