Article · Wikipedia archive · Last revised Jul 8, 2026

Gamma Ophiuchi

Gamma Ophiuchi, Latinized from γ Ophiuchi, formally named Bake-eo, is a fourth-magnitude star in the constellation Ophiuchus. Together with Beta Ophiuchi, it forms the serpent-holder's right shoulder. The star is visible to the naked eye with an apparent visual magnitude of +3.75. Based upon an annual parallax shift of 31.73 mas as seen from Earth, it is located 103 light-years from the Sun. It is moving closer to the Sun with a radial velocity of −7.6 km/s.

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γ Ophiuchi
Location of γ Ophiuchi (circled)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Ophiuchus
Right ascension 17h 47m 53.55973s1
Declination +02° 42′ 26.2000″1
Apparent magnitude (V) +3.7532
Characteristics
Evolutionary stage main sequence3
Spectral type A0 V4 or A1VnkA0mA05
U−B color index +0.0402
B−V color index +0.0332
Astrometry
Radial velocity (Rv)−7.6±0.36 km/s
Proper motion (μ) RA: −24.641 mas/yr
Dec.: −74.421 mas/yr
Parallax (π)31.73±0.21 mas1
Distance102.8 ± 0.7 ly
(31.5 ± 0.2 pc)
Absolute magnitude (MV)+1.266
Details
Mass2.94 M☉
Radius2.01±0.027 R☉
Luminosity24.5±0.57 L☉
Surface gravity (log g)4.035 cgs
Temperature9,070±1007 K
Rotational velocity (v sin i)2208 km/s
Age184+93
−1348 Myr
Other designations
Bake-eo, Bake Eo, γ Oph, 62 Ophiuchi, BD+02 3403, FK5 668, GC 24162, HD 161868, HIP 87108, HR 6629, SAO 1227549
Database references
SIMBADdata

Gamma Ophiuchi, Latinized from γ Ophiuchi, formally named Bake-eo,10 is a fourth-magnitude star in the constellation Ophiuchus. Together with Beta Ophiuchi, it forms the serpent-holder's right shoulder.11 The star is visible to the naked eye with an apparent visual magnitude of +3.75.2 Based upon an annual parallax shift of 31.73 mas as seen from Earth, it is located 103 light-years from the Sun. It is moving closer to the Sun with a radial velocity of −7.6 km/s.6

Nomenclature

This star is known also as Muliphen,1213 although at least two more stars are known with this name: Gamma Canis Majoris (often spelled as Muliphein) and Gamma Centauri (often spelled as Muhlifain).13 Muliphein is the IAU-approved name of Gamma Canis Majoris.10

This star has the Marshallese name Bake-eo (or Bake Eo, pronounced "bakey-yew"), which refers to the spondylus mussel. The IAU Working Group on Star Names approved the name Bake-eo for γ Ophiuchi on 20 August 2024 and it is now so entered in the IAU Catalog of Star Names.10

In Chinese astronomy, β Ophiuchi and γ Ophiuchi form the asterism Zongzheng (宗正),14 which was transliterated as Tsung Ching by R. H. Allen.12

Description

Image of the debris disk from the REASONS survey7

This is an A-type main-sequence star with a stellar classification of A0 V.4 Gray et al. (2003) lists a classification of A1VnkA0mA0,5 indicating it is of type A1 V with the calcium K-line and metallic lines of an A0 star. It is approximately 1848 million years old and is spinning rapidly with a projected rotational velocity of 220 km/s.8 Gamma Ophiuchi has nearly three times the mass of the Sun and 1.8 times the Sun's radius.15 The star shines with 294 times the luminosity of the Sun, which is being emitted from its outer atmosphere at an effective temperature of 9,506 K.4 It is radiating an excess emission of infrared, suggesting the presence of a circumstellar disk of dust at an orbital radius of 64 AU from the host star.4 The disk was imaged in 2025.7

The Gamma Ophiuchi planetary system7
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination
(°) 		Radius
circumstellar disc 124+6
−5 AU 		68±2° —
References

References

  1. van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics. 474 (2): 653–64. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. Cousins, A. W. J. (1984). "Standardisation of broad band photometry of equatorial standards". South Africa Astronomical Observatory Circular. 8: 59–67. Bibcode:1984SAAOC...8...59C.
  3. Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  4. Wyatt, M. C.; Smith, R.; Su, K. Y. L.; Rieke, G. H.; Greaves, J. S.; Beichman, C. A.; Bryden, G. (July 2007). "Steady State Evolution of Debris Disks around A Stars". The Astrophysical Journal. 663 (1): 365–382. arXiv:astro-ph/0703608. Bibcode:2007ApJ...663..365W. doi:10.1086/518404. S2CID 18883195.
  5. Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  6. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  7. Matrà, L.; Marino, S.; Wilner, D. J.; Kennedy, G. M.; Booth, M.; Krivov, A. V.; Williams, J. P.; Hughes, A. M.; del Burgo, C. (January 2025). "REsolved ALMA and SMA Observations of Nearby Stars (REASONS): A population of 74 resolved planetesimal belts at millimetre wavelengths". Astronomy & Astrophysics. 693: A151. arXiv:2501.09058. Bibcode:2025A&A...693A.151M. doi:10.1051/0004-6361/202451397.
  8. Song, Inseok; Caillault, J.-P.; Barrado y Navascués, David; Stauffer, John R. (February 2001). "Ages of A-Type Vega-like Stars from uvbyβ Photometry". The Astrophysical Journal. 546 (1): 352–357. arXiv:astro-ph/0010102. Bibcode:2001ApJ...546..352S. doi:10.1086/318269. S2CID 18154947.
  9. "* gam Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-01-20.
  10. "IAU Catalog of Star Names". exopla.net. Retrieved 22 February 2025.
  11. Ridpath, Ian (June 28, 2018). Star Tales. Lutterworth Press. p. 189. ISBN 9780718847821.
  12. Hinckley Allen, Richard. "LacusCurtius • Allen's Star Names — Ophiuchus". penelope.uchicago.edu. Retrieved 2017-01-03.
  13. Kaler, Jim (2009-08-28). "Muliphen". stars.astro.illinois.edu. Retrieved 2017-01-03.
  14. Ridpath, Ian. "Star Tales - Ophiuchus". Retrieved 28 July 2025.
  15. Malagnini, M. L.; Morossi, C. (November 1990). "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars". Astronomy and Astrophysics Supplement Series. 85 (3): 1015–1019. Bibcode:1990A&AS...85.1015M.