HD 37756

HD 37756
Location of HD 37756 (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Orion
Right ascension 05h 40m 50.71498s[1]
Declination −01° 07′ 43.6366″[1]
Apparent magnitude (V) 4.95[2]
Characteristics
primary
Spectral type B2IV-V[3] or B3V[4]
U−B color index −0.83[5]
B−V color index −0.21[5]
secondary
Spectral type B1[6]
Astrometry
Radial velocity (Rv)+26.10[7] km/s
Proper motion (μ) RA: −1.50[1] mas/yr
Dec.: −0.84[1] mas/yr
Parallax (π)3.63 ± 0.37 mas[1]
Distanceapprox. 900 ly
(approx. 280 pc)
Absolute magnitude (MV)−2.74[2]
Orbit[8]
Period (P)27.154925 d
Eccentricity (e)0.739±0.007
Periastron epoch (T)2447886.076±0.065 HJD
Argument of periastron (ω)
(secondary)		81.4±2.4°
Semi-amplitude (K1)
(primary)		84.7±1.1 km/s
Details
A
Mass8.6±0.2[9] M☉
Radius5.3[10] R☉
Luminosity4,830[11] L☉
Surface gravity (log g)3.84[10] cgs
Temperature21,150[11] K
Metallicity [Fe/H]+0.01[12] dex
Rotational velocity (v sin i)75[13] km/s
Age18.0±3.2[9] Myr
B
Mass8.3[6] M☉
Other designations
NSV 2556, BD−01°1004, GC 7091, HD 37756, HIP 26736, HR 1952, SAO 132445[14]
Database references
SIMBADdata

HD 37756 is a binary star system in the equatorial constellation of Orion, positioned less than a degree to the north of the bright star Alnitak.[15] It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.95.[2] The system is located at a distance of approximately 900 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +26 km/s.[7] It is a member of the OB1b subgroup of the Orion OB1 association.[16]

The binary nature of this system was identified by E. B. Frost in 1904.[17] It is a double-lined spectroscopic binary with an orbital period of 27.15 days and a high eccentricity of 0.74.[8] The spectrum matches a massive B-type main-sequence star with a stellar classification of B3V.[4] The secondary is luminous enough to interfere with measurements of the primary spectrum.[17] It is a suspected Cepheid variable with a period of 0.37968 days and an amplitude of 0.03 magnitude in the B band of the UBV photometric system.[18] The system is a candidate eclipsing binary with a minimum dip of 0.04 in visual magnitude during each orbit.[19]

  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 Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Hoffleit1991 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Mallama2014 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Kraicheva1980 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Hilditch1991 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference McDonald2017 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Abt2002 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Sinnott1997 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Voss2010 was invoked but never defined (see the help page).
  17. ^ a b Cite error: The named reference Kameswara1990 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Hill1967 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Hoffleit1996 was invoked but never defined (see the help page).