Gamma Ophiuchi

Gamma Ophiuchi, Latinized from γ Ophiuchi, also named Bake-eo,^[9] is a fourth-magnitude star in the constellation Ophiuchus. Together with Beta Ophiuchi, it forms the serpent-holder's right shoulder.^[10] 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.^[5]

γ Ophiuchi

Location of γ Ophiuchi (circled)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Ophiuchus
Right ascension	17h 47m 53.55973s[1]
Declination	+02° 42′ 26.2000″[1]
Apparent magnitude (V)	+3.753[2]
Characteristics
Spectral type	A0 V[3] or A1VnkA0mA0[4]
U−B color index	+0.040[2]
B−V color index	+0.033[2]
Astrometry
Radial velocity (Rv)	−7.6±0.3[5] km/s
Proper motion (μ)	RA: −24.64[1] mas/yr Dec.: −74.42[1] mas/yr
Parallax (π)	31.73±0.21 mas[1]
Distance	102.8 ± 0.7 ly (31.5 ± 0.2 pc)
Absolute magnitude (MV)	+1.26[5]
Details
Mass	2.9[3] M☉
Radius	1.91[6] R☉
Luminosity	29[3] L☉
Surface gravity (log g)	4.03[4] cgs
Temperature	9,506[3] K
Rotational velocity (v sin i)	220[7] km/s
Age	184+93 −134[7] 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 122754[8]
Database references
SIMBAD	data

Nomenclature

This star is known also as Muliphen,^[11][12] 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).^[12] Muliphein is the IAU-approved name of Gamma Canis Majoris.^[9]

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 this star on 20 August 2024 and it is now so entered in the IAU Catalog of Star Names.^[9]

In Chinese astronomy, β Ophiuchi and γ Ophiuchi form the asterism Zongzheng (宗正),^[13] which was transliterated as Tsung Ching by R. H. Allen.^[11]

Description

Image of the debris disk from the REASONS survey^[14]

This is an A-type main sequence star with a stellar classification of A0 V.^[3] Gray et al. (2003) lists a classification of A1VnkA0mA0,^[4] indicating it is of type A1 V with the calcium K-line and metallic lines of an A0 star. It is approximately 184^[7] million years old and is spinning rapidly with a projected rotational velocity of 220 km/s.^[7] Gamma Ophiuchi has nearly three times the mass of the Sun and 1.8 times the Sun's radius.^[15] The star shines with 29^[3] times the luminosity of the Sun, which is being emitted from its outer atmosphere at an effective temperature of 9506 K.^[3] 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.^[3] The disk was imaged in 2025.^[14]

The Gamma Ophiuchi planetary system^[14]

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