Gamma Coronae Australis
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Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
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Constellation | Corona Australis |
Right ascension | 19h 06m 25.11014s[1] |
Declination | −37° 03′ 48.3901″[1] |
Apparent magnitude (V) | 4.20[2] |
Characteristics | |
Spectral type | F8V + F8V[3] |
U−B color index | +0.51[4] |
B−V color index | +0.01[4] |
Astrometry | |
Radial velocity (Rv) | −51.60±0.3[5] km/s |
Proper motion (μ) | RA: 96.74±1.05[1] mas/yr Dec.: −281.71±0.58[1] mas/yr |
Parallax (π) | 57.79 ± 0.75 mas[1] |
Distance | 56.4 ± 0.7 ly (17.3 ± 0.2 pc) |
Absolute magnitude (MV) | 3.73 / 3.80[6] |
Orbit[7] | |
Period (P) | 121.76 yr |
Semi-major axis (a) | 1.896″ |
Eccentricity (e) | 0.320 |
Inclination (i) | 149.6° |
Longitude of the node (Ω) | 50.3° |
Periastron epoch (T) | 2000.64 |
Argument of periastron (ω) (secondary) | 349.0° |
Details[6] | |
γ CrA A | |
Mass | 1.15 M☉ |
Radius | 1.47 R☉ |
Surface gravity (log g) | 4.17 cgs |
Temperature | 6,090 K |
Metallicity [Fe/H] | −0.07 dex |
Age | 5 Gyr |
γ CrA B | |
Mass | 1.14 M☉ |
Radius | 1.42 R☉ |
Surface gravity (log g) | 4.19 cgs |
Temperature | 6,100 K |
Metallicity [Fe/H] | −0.07 dex |
Age | 5 Gyr |
Other designations | |
γ CrA A: HD 177474, HR 7226[8] | |
γ CrA B: HD 177475, HR 7227[9] | |
Database references | |
SIMBAD | γ CrA |
γ CrA A | |
γ CrA B |
Gamma Coronae Australis (γ CrA), is a binary star located in the constellation Corona Australis. The system has a combined apparent visual magnitude of 4.20,[2] making it faintly visible to the naked eye. It is located 56.4 light-years (17.3 parsecs) from the Sun, based on its parallax.[1] Gamma Coronae Australis is a member of the Milky Way's thin disk.[6]
The system is a visual binary, where the orbit is calculated from observations of one star orbiting the other. The primary, Gamma Coronae Australis A, is a late F-type main-sequence star with an effective temperature of 6,090 K.[6] It has an absolute an absolute magnitude of +3.73, and a mass of 1.15 solar masses.[6] The secondary, Gamma Coronae Australis B, is also F-type. With an effective temperature of 6,100 K, an absolute magnitude of +3.80, and a mass of 1.14 solar masses, the companion is almost identical to the primary.[6] Gamma Coronae Australis has been known to be a binary for a long time, and its two components have been given Henry Draper Catalogue designations of HD 177474[8] and HD 177475,[9] respectively. The two stars are separated by 1.896″ and orbit each other every 121.76 years.[7]
References
- ^ a b c d e f van Leeuwen, F. (November 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.
- ^ a b c "* gam CrA". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 June 2017.
- ^ Eggl, S.; Pilat-Lohinger, E.; Funk, B.; Georgakarakos, N.; Haghighipour, N. (2012). "Circumstellar habitable zones of binary-star systems in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 428 (4): 3104. arXiv:1210.5411. Bibcode:2013MNRAS.428.3104E. doi:10.1093/mnras/sts257.
- ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ a b c d e f Fuhrmann, K.; Chini, R. (2015). "Multiplicity Among F-Type Stars. II". The Astrophysical Journal. 809 (1): 107. Bibcode:2015ApJ...809..107F. doi:10.1088/0004-637X/809/1/107. S2CID 126218052.
- ^ a b "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 20 June 2017.
- ^ a b "* gam CrA A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 June 2017.
- ^ a b "* gam CrA B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 June 2017.
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