Gamma Circini, Latinized from γ Circini, is a star system in the constellation Circinus. It was noted as a double star by Herschel in 1835, who estimated the separation as 1 arc second.[11] It is visible to the naked eye with an apparent visual magnitude of 4.51.[2] Based upon an annual parallax shift of 7.27 mas,[1] it is about 450 light-years away.
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Circinus |
Right ascension | 15h 23m 22.64294s[1] |
Declination | −59° 19′ 14.8131″[1] |
Apparent magnitude (V) | 4.51[2] (4.94 + 5.73)[3] |
Characteristics | |
Spectral type | B5 IV[4] + F8 V[2] |
Variable type | Be[5] |
Astrometry | |
Radial velocity (Rv) | 16.90±1.78[6] km/s |
Proper motion (μ) | RA: −12.97[1] mas/yr Dec.: −34.24[1] mas/yr |
Parallax (π) | 7.27 ± 0.81 mas[1] |
Distance | approx. 450 ly (approx. 140 pc) |
Absolute magnitude (MV) | −1.18[7] |
Orbit[4] | |
Period (P) | 258 yr |
Semi-major axis (a) | 2.576″ |
Eccentricity (e) | 0.931 |
Details | |
γ Cir A | |
Mass | 6.0±0.3[8] M☉ |
Temperature | 15,135[9] K |
Age | 63.1±19.6[8] Myr |
γ Cir B | |
Temperature | 4,786[9] K |
Other designations | |
γ Cir A: HD 136415 | |
γ Cir B: HD 136416 | |
Database references | |
SIMBAD | γ Cir AB |
γ Cir A | |
γ Cir B |
This is a wide binary star system and may even be a triple star.[9] The two visible components orbit each other with a preliminary estimated period of 258 years and a large eccentricity of 0.931.[4] As of 2014, the visible components have an angular separation of 0.80 arc seconds on a position angle of 359°.[3]
The primary star, component A, is a B-type subgiant star with a stellar classification of B5 IV.[4] Based upon isochrone curve fitting it is hypothesized to be a pair of matching B5 stars,[9] and is a Be variable with an uncertain maximum.[5] It has an effective temperature of 15,135[9] K and an estimated mass six[8] times that of the Sun. The companion, component B, is an F-type main-sequence star with a stellar classification of F8 V.[2] It has an effective temperature of 4,786[9] K.
{{cite web}}
: CS1 maint: postscript (link)