Gamma Circini

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γ Circini
Circinus IAU.svg
Red circle.svg

Location of y Circini (circled)
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[1] mas
Distance approx. 450 ly
(approx. 140 pc)
Absolute magnitude (MV) −2.3/−2.6
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[7] M
Temperature 15,135[8] K
Age 63.1±19.6[7] Myr
γ Cir B
Temperature 4,786[8] K
Other designations
γ Cir, HIP 75323, HR 5704, SAO 242463.[9]
γ Cir A: HD 136415
γ Cir B: HD 136416

Gamma Circini (γ Cir) is a star system located in the constellation Circinus. It was noted as a double star by Herschel in 1835, who estimated their separation as 1 arc second.[10] 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] is it located at a distance of approximately 450 light years.

This is a wide binary star system and may even be a triple star.[8] 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 along a position angle of 359°.[3]

The primary star, component A, is a B-type subgiant star with a stellar classification of B5 VI.[4] Based upon isochrone curve fitting it is hypothesized to be a pair of matching B5 stars,[8] and is a Be variable with an uncertain maximum.[5] It has an effective temperature of 15,135[8] K and an estimated mass six[7] 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[8] K.

References[edit]

  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Buscombe, W.; Barkstrom, B. (1971), "The composite spectrum of gamma Circini", Monthly Notices of the Royal Astronomical Society, 152: 37−45, Bibcode:1971MNRAS.152...37B, doi:10.1093/mnras/152.1.37. 
  3. ^ a b Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22 
  4. ^ a b c d Malkov, O. Yu.; et al. (2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546: A69, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774. 
  5. ^ a b Kazarovets, E. V.; et al. (1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K. 
  6. ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048Freely accessible, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61. 
  7. ^ a b c Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883Freely accessible, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x. 
  8. ^ a b c d e f Parsons, Sidney B. (May 2004), "New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions", The Astronomical Journal, 127 (5): 2915−2930, Bibcode:2004AJ....127.2915P, doi:10.1086/383546. 
  9. ^ "gam Cir -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-01-13. 
  10. ^ Carette, E.; et al. (April 1995), "γ Circinus: a young visual binary with pre-main-sequence component(s)?", Astronomy and Astrophysics, 296: 139, Bibcode:1995A&A...296..139C. 

External links[edit]