HD 37017
Observation data
Epoch J2000      Equinox J2000
Constellation Orion
Right ascension 05h 35m 21.86770s[1]
Declination −04° 29′ 39.0409″[1]
Apparent magnitude (V) 6.553[2]
Spectral type B1.5 Vp He strong[3]
U−B color index −0.79[4]
B−V color index −0.14[4]
Variable type SX Ari[5]
Radial velocity (Rv)+32±2[6] km/s
Proper motion (μ) RA: 1.88±0.09[7] mas/yr
Dec.: 1.20±0.14[7] mas/yr
Parallax (π)2.643 ± 0.075[7] mas
Distance1,230 ± 40 ly
(380 ± 10 pc)
Period (P)18.6556±0.0017 d
Semi-major axis (a)≥12.61±1.09 R
Eccentricity (e)0.31±0.05
Periastron epoch (T)2,435,461.602±0.168 JD
Argument of periastron (ω)
Semi-amplitude (K1)
36.0±2.5 km/s
Mass8.50±0.53[2] M
Luminosity3,754[2] L
Temperature23,700[2] K
Rotation0.901 d[9]
Rotational velocity (v sin i)165[3] km/s
Mass4.5[8] M
Other designations
V1046 Orionis, BD−04°1183, HD 37017, HIP 26233, HR 1890, SAO 132317[10]
Database references

HD 37017 is a binary star system in the equatorial constellation of Orion. It has the variable star designation V1046 Orionis; HD 37017 is the identifier from the Henry Draper Catalogue. The system is a challenge to view with the naked eye, being close to the lower limit of visibility with a combined apparent visual magnitude of 6.55.[2] It is located at a distance of approximately 1,230 light years based on parallax,[7] and is drifting further away with a radial velocity of +32 km/s.[6] The system is part of star cluster NGC 1981.[11]

The binary nature of this system was suggested by A. Blaauw and T. S. van Albada in 1963.[8] It is a double-lined[9] spectroscopic binary with an orbital period of 18.6556 days and an eccentricity of 0.31.[12] The eccentricity is considered unusually large for such a close system.[9] It forms a suspected eclipsing binary that ranges in brightness from 6.54 down to 6.58.[5]

The primary is a helium-strong, magnetic chemically peculiar star[13] with a stellar classification of B1.5 Vp.[3] It has a magnetic field strength of 7,700 G,[14] and the helium concentrations are located at the magnetic poles.[15] V1046 Orionis was found to be a variable star by L. A. Balona in 1997,[9] and is now classified as an SX Arietis variable.[5] The star undergoes periodic changes in visual brightness, magnetic field strength, and spectral characteristics with a cycle time of 0.901175 days – the star's presumed rotation period.[9] Radio emission has been detected that varies with the rotation period.[15]

The secondary component has an estimated 4.5 times the mass of the Sun. The class has been estimated as type B6III-IV.[9]


  1. ^ a b 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.
  2. ^ a b c d e Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349–360, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
  3. ^ a b c Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
  4. ^ a b Walker, M. F. (February 1969), "Studies of extremely young clusters. V. Stars in the vicinity of the Orion nebula", Astrophysical Journal, 155: 447, Bibcode:1969ApJ...155..447W, doi:10.1086/149881.
  5. ^ a b c Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  6. ^ a b Blaauw, A.; et al. (April 1963), "Radial Velocities of B-Type Stars in the Nearest Associations.", Astrophysical Journal, 137: 791, Bibcode:1963ApJ...137..791B, doi:10.1086/147556.
  7. ^ a b c d Kounkel, Marina; et al. (2017), "The Gould's Belt Distances Survey (GOBELINS) II. Distances and Structure toward the Orion Molecular Clouds", The Astrophysical Journal, 834 (2), 142, arXiv:1609.04041, Bibcode:2017ApJ...834..142K, doi:10.3847/1538-4357/834/2/142, hdl:1887/59417, S2CID 26439367.
  8. ^ a b c Leone, F.; Catanzaro, G. (March 1999), "Orbital elements of binary systems with a chemically peculiar star", Astronomy and Astrophysics, 343: 273–280, Bibcode:1999A&A...343..273L.
  9. ^ a b c d e f Bolton, C. T.; et al. (September 1998), "HD 37017 = V 1046 ORI A double-lined spectroscopic binary with a B2e He-strong magnetic primary", Astronomy and Astrophysics, 337: 183–197, Bibcode:1998A&A...337..183B.
  10. ^ "V1046 Ori". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-12-31.
  11. ^ Maia, F. F. S.; et al. (September 2010), "Characterization and photometric membership of the open cluster NGC1981", Monthly Notices of the Royal Astronomical Society, 407 (3): 1875–1886, arXiv:1005.3047, Bibcode:2010MNRAS.407.1875M, doi:10.1111/j.1365-2966.2010.17034.x, S2CID 119206669.
  12. ^ Ducati, J. R.; et al. (January 2011), "The mass ratio and initial mass functions in spectroscopic binaries" (PDF), Astronomy and Astrophysics, 525: 9, Bibcode:2011A&A...525A..26D, doi:10.1051/0004-6361/200913895, A26.
  13. ^ Ghazaryan, S.; et al. (August 2019), "Statistical analysis of roAp, He-weak, and He-rich stars", Monthly Notices of the Royal Astronomical Society, 487 (4): 5922–5931, arXiv:1906.06984, Bibcode:2019MNRAS.487.5922G, doi:10.1093/mnras/stz1678, S2CID 189928323.
  14. ^ Trigilio, C.; et al. (May 2004), "A three-dimensional model for the radio emission of magnetic chemically peculiar stars", Astronomy and Astrophysics, 418 (2): 593–605, arXiv:astro-ph/0402432, Bibcode:2004A&A...418..593T, doi:10.1051/0004-6361:20040060, S2CID 15884571.
  15. ^ a b Leone, F.; Umana, G. (January 1993), Dworetsky, M. M.; Castelli, F.; Faraggiana, R. (eds.), "Periodic Radio Emission from the Helium Rich Stars HD 37017 and σ Ori E", Peculiar versus Normal Phenomena in A-type and Related Stars. International Astronomical Union, Colloquium No. 138, held in Trieste, Italy, July 1992, San Francisco: Astronomical Society of the Pacific, 44 (138), p. 541, Bibcode:1993ASPC...44..541L.