Location of γ Coronae Australis (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 19 06 25.11014 |
| Declination | −37° 03′ 48.3901″ |
| Apparent magnitude (V) | 4.20 |
| Characteristics | |
| Spectral type | F8V + F8V |
| U−B color index | +0.51 |
| B−V color index | +0.01 |
| Astrometry | |
| Radial velocity (Rv) | −51.60±0.3 km/s |
| Proper motion (μ) | RA: 96.74±1.05 mas/yr Dec.: −281.71±0.58 mas/yr |
| Parallax (π) | 57.79 ± 0.75 mas |
| Distance | 56.4 ± 0.7 ly (17.3 ± 0.2 pc) |
| Absolute magnitude (MV) | 3.73 / 3.80 |
| Orbit | |
| 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 | |
| γ CrA A | |
| Mass | 1.15 M☉ |
| Radius | 1.47 R☉ |
| Surface gravity (log g) | 4.17 cgs |
| Temperature | 6,090 K |
| Metallicity | −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 | −0.07 dex |
| Age | 5 Gyr |
| Other designations | |
| γ CrA, CD−37°13048, HIP 93825, SAO 210928, CCDM J19064-3704 | |
| γ CrA A: HD 177474, HR 7226 | |
| γ CrA B: HD 177475, HR 7227 | |
| 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, 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. Gamma Coronae Australis is a member of the Milky Way's thin disk.
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. It has an absolute an absolute magnitude of +3.73, and a mass of 1.15 solar masses. 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. 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 and HD 177475, respectively. The two stars are separated by 1.896″ and orbit each other every 121.76 years.
References
- ^ 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.
- ^ "* 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.
- ^ 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.
- ^ 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.
- ^ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 20 June 2017.
- ^ "* gam CrA A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 June 2017.
- ^ "* gam CrA B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 June 2017.
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