HD 37756
Red circle.svg
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]
Spectral type B2IV-V[3] or B3V[4]
U−B color index −0.83[5]
B−V color index −0.21[5]
Radial velocity (Rv)+26.10[6] km/s
Proper motion (μ) RA: −1.50[1] mas/yr
Dec.: −0.84[1] mas/yr
Parallax (π)3.63 ± 0.37[1] mas
Distanceapprox. 900 ly
(approx. 280 pc)
Absolute magnitude (MV)−2.74[2]
Period (P)27.154925 d
Eccentricity (e)0.739±0.007
Periastron epoch (T)2447886.076±0.065 HJD
Argument of periastron (ω)
Semi-amplitude (K1)
84.7±1.1 km/s
Mass8.6±0.2[8] M
Luminosity4830[9] L
Temperature21,150[9] K
Metallicity [Fe/H]+0.01[10] dex
Rotational velocity (v sin i)75[11] km/s
Age18.0±3.2[8] Myr
Other designations
NSV 2556, BD−01°1004, GC 7091, HD 37756, HIP 26736, HR 1952, SAO 132445[12]
Database references

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.[13] 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.[6] It is a member of the OB1b subgroup of the Orion OB1 Association.[14]

The binary nature of this system was identified by E. B. Frost in 1904.[15] It is a double-lined spectroscopic binary with an orbital period of 27.15 days and a high eccentricity of 0.74.[7] 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.[15] 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.[16] The system is a candidate eclipsing binary with a minimum dip of 0.04 in visual magnitude during each orbit.[17]


  1. ^ a b c d e f 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. Vizier catalog entry
  2. ^ a b c 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. Vizier catalog entry
  3. ^ Hoffleit, D.; Warren, W. H. (1995). "Bright Star Catalogue". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H (5th Revised ed.). 5050. Bibcode:1995yCat.5050....0H.
  4. ^ a b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  5. ^ a b Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  6. ^ a b Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. LCCN 54001336.
  7. ^ a b Hilditch, R. W.; et al. (February 1991). "The eccentric-orbit binaries Iota Orionis and HD 1952: a cautionary tale". The Observatory. 111: 14–20. Bibcode:1991Obs...111...14H.
  8. ^ a b Tetzlaff, N.; et al. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873. Vizier catalog entry
  9. ^ a b Hohle, M. M.; et al. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID 111387483. Vizier catalog entry
  10. ^ Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. S2CID 118345778. Vizier catalog entry
  11. ^ Abt, Helmut A.; et al. (2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573 (1): 359–365. Bibcode:2002ApJ...573..359A. doi:10.1086/340590.
  12. ^ "HD 37756". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-11-20.
  13. ^ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. 1. Sky Publishing Corporation and the European Space Agency. p. 253. ISBN 0-933346-84-0.
  14. ^ Voss, R.; et al. (September 2010). "Probing the evolving massive star population in Orion with kinematic and radioactive tracers". Astronomy and Astrophysics. 520: 10. arXiv:1005.3827. Bibcode:2010A&A...520A..51V. doi:10.1051/0004-6361/201014408. S2CID 38599952. A51.
  15. ^ a b Rao, N. Kameswara; et al. (1990). "The eccentric double-lined binary BD — 1° 1004". Journal of Astrophysics and Astronomy. 11 (4): 445. Bibcode:1990JApA...11..445K. doi:10.1007/BF02709760. S2CID 73616576.
  16. ^ Hill, Graham (August 1967). "On Beta Cephei Stars: a Search for Beta Cephei Stars". Astrophysical Journal Supplement. 14: 263. Bibcode:1967ApJS...14..263H. doi:10.1086/190156.
  17. ^ Hoffleit, Dorrit (1996). "A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars". The Journal of the American Association of Variable Star Observers. 24 (2): 105–116. Bibcode:1996JAVSO..24..105H.