| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Carina |
| Right ascension | 09 05 08.81309 |
| Declination | −72° 36′ 09.7437″ |
| Apparent magnitude (V) | 4.48 + 14.50 |
| Characteristics | |
| Spectral type | F8II + DA1.6 |
| B−V color index | +0.607±0.010 |
| Astrometry | |
| Radial velocity (Rv) | +22.5±0.7 km/s |
| Proper motion (μ) | RA: −8.81 mas/yr Dec.: −5.26 mas/yr |
| Parallax (π) | 8.14 ± 0.15 mas |
| Distance | 401 ± 7 ly (123 ± 2 pc) |
| Absolute magnitude (MV) | −0.98 |
| Details | |
| A | |
| Radius | 13.15+1.03 −0.53 R☉ |
| Luminosity | 206.2±5.4 L☉ |
| Temperature | 6,030+127 −222 K |
| Metallicity | −0.04±0.04 dex |
| Rotational velocity (v sin i) | 53 km/s |
| B | |
| Mass | 0.74 M☉ |
| Surface gravity (log g) | 7.47 cgs |
| Temperature | 21,551 K |
| Age | 25 Myr |
| Other designations | |
| G Car, CPD−72°779, FK5 2720, GC 12595, HD 78791, HIP 44599, HR 3643, SAO 256582, WDS J17039+1941, WD 0905-724 | |
| Database references | |
| SIMBAD | data |
HR 3643 is a binary star system in the southern constellation of Carina. It has the Bayer designation G Carinae, with HR 3643 being the star's designation in the Bright Star Catalogue. The system is visible to the naked eye with an apparent visual magnitude of 4.48. It is located at a distance of approximately 401 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +22.5 km/s.
The binary nature of this system was first detected as an ultraviolet excess in 1996. No radial velocity variation has been detected so it must be a wide system with an orbital period of up to 21 years. The estimated semimajor axis of their orbit is 10.90 AU. The pair were not resolved using the Hubble Space Telescope WFPC2 instrument.
The primary is an evolved bright giant star with a yellow-white hue and a stellar classification of F8II. With the supply of hydrogen exhausted at its core, it has expanded to 13 times the Sun's radius. It has a relatively high projected rotational velocity of 53 km/s for a star of this class, suggesting it is an intermediate-mass star with 2–5 times the mass of the Sun. The star is radiating 206 times the luminosity of the Sun from its photosphere at an effective temperature of 6,030 K.
The magnitude 14.50 companion is a white dwarf with a class of DA1.6. It has a mass estimated at 74% of the mass of the Sun and a temperature of 21,551 K, indicating a cooling time of 25 million years. This object is a source for hard X-ray emission. The primary is one of the most massive stars known to have a white dwarf companion.
References
- ^ 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.
- ^ Holberg, J. B.; et al. (2013), "Where are all the Sirius-like binary systems?", Monthly Notices of the Royal Astronomical Society, 435 (3): 2077, arXiv:1307.8047, Bibcode:2013MNRAS.435.2077H, doi:10.1093/mnras/stt1433.
- ^ Skiff, B. A. (October 2014), "Catalogue of Stellar Spectral Classifications", VizieR On-line Data Catalog: B/mk. Originally published in: Lowell Observatory (October 2014), Bibcode:2014yCat....1.2023S.
- ^ 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, S2CID 119257644.
- ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 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.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Landsman, Wayne; et al. (March 1996), "The White-Dwarf Companions of 56 Persei and HR 3643", Publications of the Astronomical Society of the Pacific, 108: 250, arXiv:astro-ph/9512117, Bibcode:1996PASP..108..250L, doi:10.1086/133718, S2CID 14398914.
- ^ Barstow, M. A.; et al. (May 2014), "Evidence for an external origin of heavy elements in hot DA white dwarfs", Monthly Notices of the Royal Astronomical Society, 440 (2): 1607–1625, arXiv:1402.2164, Bibcode:2014MNRAS.440.1607B, doi:10.1093/mnras/stu216.
- "G Car". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-12-11.
- ^ Barstow, M. A.; et al. (April 2001), "Resolving Sirius-like binaries with the Hubble Space Telescope", Monthly Notices of the Royal Astronomical Society, 322 (4): 891–900, arXiv:astro-ph/0010645, Bibcode:2001MNRAS.322..891B, doi:10.1046/j.1365-8711.2001.04203.x, S2CID 12232120.
- Bilíková, Jana; et al. (November 2010), "Hard X-ray Emission Associated with White Dwarfs. III", The Astronomical Journal, 140 (5): 1433–1443, Bibcode:2010AJ....140.1433B, doi:10.1088/0004-6256/140/5/1433.
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