HD 64740

HD 64740
Location of HD 64740 (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Puppis
Right ascension 07h 53m 03.63538s[1]
Declination −49° 36′ 46.9530″[1]
Apparent magnitude (V) 4.63[2]
Characteristics
Spectral type B2V[3]
U−B color index −0.92[2]
B−V color index −0.23[2]
Variable type Constant[4]
Astrometry
Radial velocity (Rv)+8.00±4.2[5] km/s
Proper motion (μ) RA: −7.77[1] mas/yr
Dec.: +15.16[1] mas/yr
Parallax (π)4.30 ± 0.15 mas[1]
Distance760 ± 30 ly
(233 ± 8 pc)
Absolute magnitude (MV)−2.2±0.1[6]
Details
Mass9.6 M☉[7]
10.1±0.5[8] M☉
Radius4.5±0.7[8] R☉
Luminosity5,908[9] L☉
Surface gravity (log g)4.01±0.09[6] cgs
Temperature23,700[9] K
Metallicity [Fe/H]+0.01[10] dex
Rotation1.33026 d[11]
Rotational velocity (v sin i)160[12] km/s
Age12.6+7.4
−2.7[8] Myr
Other designations
CD−49°3137, CPD−49°1398, GC 10686, HD 64740, HIP 38500, HR 3089, SAO 219106, GSC 08143-03240
Database references
SIMBADdata

HD 64740 is a single[13] star in the southern constellation Puppis, positioned near the line of sight to the Gum Nebula.[4] It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.63.[2] Parallax measurements give a distance estimate of approximately 760 light-years from the Sun,[1] and it is drifting further away with a radial velocity of +8 km/s.[5]

This is a massive B-type main-sequence star with a stellar classification of B2V.[3] It is a magnetic chemically peculiar star of the helium strong variety[6] with weak hydrogen alpha emission.[8] The polar magnetic field strength is 3,700 G.[4] The star is about halfway through its main sequence lifetime with an estimated age of ~13 million years.[8] It is spinning rapidly with an equatorial velocity of about 140±10 km/s, based on a polar inclination angle of 36°±15°,[4] giving it a rotation period of ~1.33 days.[11] The star is radiating over 5,900 times the luminosity of the Sun from its photosphere at an effective temperature of 23,700 K.[9]

Significant X-ray emission has been detected originating from this star, which may be connected to the magnetically-confined stellar wind.[14] The star does not display pulsation behavior, but it does show a magnetically-modulated variation from the wind.[15] Variation of ultraviolet lines of silicon has been detected, which may be due to surface abundance variations.[4] Two patches of helium overabundance are observed near the magnetic poles, which are inclined by about 20° to the star's pole of rotation.[11]

  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 Cite error: The named reference Ducati2002 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1978 was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference Krtička_et_al_2013 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 Cite error: The named reference Schulz_et_al_2019a was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  8. ^ a b c d e Cite error: The named reference Shultz_et_al_2019b was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Alecian_et_al_2012 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Hoffleit1991 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Chini_et_al_2012 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Nazé_et_al_2014 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Telting_et_al_2006 was invoked but never defined (see the help page).