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.

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]

In 2025 the star was found to have a weak magnetic field, which is unusual for giant stars. It is considered an example of an transitional object between main sequence strongly magnetic stars and magnetic supergiants like Alnitak.[7]

References

  1. ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. ^ a b c d e 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.
  3. ^ 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.
  4. ^ 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.
  5. ^ 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
  6. ^ Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Washington, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W
  7. ^ a b c d e f g h i Barron, James A.; Wade, Gregg A.; Holgado, Gonzalo; Simón-Díaz, Sergio (2025-05-16), A magnetic field detection in the massive O-type bright giant 63 Oph, arXiv:2505.11374
  8. ^ Blex, Susanne; Haas, Martin; Chini, Rolf (2024). "The rotation rate of single- and double-lined southern O stars: Determining what increases the rotation rate in binaries". Astronomy and Astrophysics. 692. Bibcode:2024A&A...692A.192B. doi:10.1051/0004-6361/202450176.
  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