Gamma Circini

γ Circini
Location of y Circini (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Circinus
Right ascension 15h 23m 22.64294s
Declination −59° 19′ 14.8131″
Apparent magnitude (V) 4.51 (4.94 + 5.73)
Characteristics
Spectral type B5 IV + F8 V
Variable type Be
Astrometry
Radial velocity (Rv)16.90±1.78 km/s
Proper motion (μ) RA: −12.97 mas/yr
Dec.: −34.24 mas/yr
Parallax (π)7.27±0.81 mas
Distanceapprox. 450 ly
(approx. 140 pc)
Absolute magnitude (MV)−1.18
Orbit
Period (P)258 yr
Semi-major axis (a)2.576″
Eccentricity (e)0.931
Details
γ Cir A
Mass6.0±0.3 M☉
Temperature15,135 K
Age63.1±19.6 Myr
γ Cir B
Temperature4,786 K
Other designations
γ Cir, CPD−58°5908, HIP 75323, HR 5704, SAO 242463
γ Cir A: HD 136415
γ Cir B: HD 136416
Database references
SIMBADγ Cir AB
γ Cir A
γ Cir B

Gamma Circini is a star system in the constellation Circinus. Its name is a Bayer designation that is Latinized from γ Circini, and abbreviated Gamma Cir or γ Cir. This was noted as a double star by Herschel in 1835, who estimated the separation as 1 arc second. It is visible to the naked eye as a point of light with a combined apparent visual magnitude of 4.51. Based upon an annual parallax shift of 7.27 mas, it is about 450 light-years away.

A light curve for Gamma Circini, plotted from TESS data

This is a wide binary star system and may even be a triple star. The two visible components orbit each other with a preliminary estimated period of 258 years and a large eccentricity of 0.931. As of 2014, the visible components have an angular separation of 0.80 arc seconds on a position angle of 359°.

The primary star, component A, is a B-type subgiant star with a stellar classification of B5 IV. Based upon isochrone curve fitting it is hypothesized to be a pair of matching B5 stars, and is a Be variable with an uncertain maximum. It has an effective temperature of 15,135 K and an estimated mass six times that of the Sun. The companion, component B, is an F-type main-sequence star with a stellar classification of F8 V. It has an effective temperature of 4,786 K.

References

  1. 1 2 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. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  3. 1 2 3 4 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.
  4. 1 2 Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
  5. 1 2 3 4 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.
  6. 1 2 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.
  7. ↑ 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:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  8. 1 2 3 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:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
  9. 1 2 3 4 5 6 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.
  10. ↑ "* gam Cir", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-01-13.
  11. ↑ 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.
  12. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 29 December 2022.