HR 3643

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]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d e f g h i Cite error: The named reference Holberg2013 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Skiff2014 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference Landsman1996 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Barstow2014 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Barstow2001 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Bilíková2010 was invoked but never defined (see the help page).