HR 3643
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension 09h 05m 08.81309s[1]
Declination −72° 36′ 09.7437″[1]
Apparent magnitude (V) 4.48 + 14.50[2]
Characteristics
Spectral type F8II[3] + DA1.6[2]
B−V color index +0.607±0.010[4]
Astrometry
Radial velocity (Rv)+22.5±0.7[5] km/s
Proper motion (μ) RA: −8.81[1] mas/yr
Dec.: −5.26[1] mas/yr
Parallax (π)8.14 ± 0.15 mas[1]
Distance401 ± 7 ly
(123 ± 2 pc)
Absolute magnitude (MV)−0.98[4]
Details
A
Radius13.15+1.03
−0.53[6] R☉
Luminosity206.2±5.4[6] L☉
Temperature6,030+127
−222[6] K
Metallicity [Fe/H]−0.04±0.04[4] dex
Rotational velocity (v sin i)53[7] km/s
B
Mass0.74[2] M☉
Surface gravity (log g)7.47[8] cgs
Temperature21,551[8] K
Age25[8] 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[9]
Database references
SIMBADdata

HR 3643 is a binary star[2][7] 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.[2] It is located at a distance of approximately 401 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +22.5 km/s.[5]

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.[10] The estimated semimajor axis of their orbit is 10.90 AU.[2] The pair were not resolved using the Hubble Space Telescope WFPC2 instrument.[10]

The primary is an evolved bright giant star with a yellow-white hue and a stellar classification of F8II.[3] With the supply of hydrogen exhausted at its core, it has expanded to 13[6] 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.[7] The star is radiating 206[6] times the luminosity of the Sun from its photosphere at an effective temperature of 6,030 K.[6]

The magnitude 14.50[2] companion is a white dwarf with a class of DA1.6.[2] It has a mass estimated at 74%[2] of the mass of the Sun and a temperature of 21,551 K, indicating a cooling time of 25 million years.[8] This object is a source for hard X-ray emission.[11] The primary is one of the most massive stars known to have a white dwarf companion.[7]

References

  1. 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.
  2. 1 2 3 4 5 6 7 8 9 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.
  3. 1 2 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.
  4. 1 2 3 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.
  5. 1 2 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.
  6. 1 2 3 4 5 6 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.
  7. 1 2 3 4 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.
  8. 1 2 3 4 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.
  9. ↑ "G Car". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-12-11.
  10. 1 2 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.
  11. ↑ 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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