HD 37017
Binary star system in the constellation Orion
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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 6.6. It is located at a distance of approximately 1,230 light years based on parallax,[10] and is drifting further away with a radial velocity of +32 km/s.[9] The system is part of star cluster NGC 1981.[15]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion[2] |
| Right ascension | 05h 35m 21.86770s[3] |
| Declination | −04° 29′ 39.0409″[3] |
| Apparent magnitude (V) | 6.555 – 6.571[4] |
| Characteristics | |
| Evolutionary stage | B2/3V[5] (B1.5 Vp He strong[6]) |
| U−B color index | −0.79[7] |
| B−V color index | −0.14[7] |
| Variable type | SX Ari[8] |
| Astrometry | |
| Radial velocity (Rv) | +32±2[9] km/s |
| Proper motion (μ) | RA: 1.88±0.09[10] mas/yr Dec.: 1.20±0.14[10] mas/yr |
| Parallax (π) | 2.643±0.075 mas[10] |
| Distance | 1,230 ± 40 ly (380 ± 10 pc) |
| Absolute magnitude (MV) | −1.2[2] |
| Orbit[11] | |
| 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) (secondary) | 133±5° |
| Semi-amplitude (K1) (primary) | 36.0±2.5 km/s |
| Details | |
| A | |
| Mass | 8.50±0.53[12] M☉ |
| Luminosity | 3,754[12] L☉ |
| Temperature | 23,700[12] K |
| Rotation | 0.901 d[13] |
| Rotational velocity (v sin i) | 165[6] km/s |
| B | |
| Mass | 4.5[11] M☉ |
| Other designations | |
| V1046 Orionis, BD−04°1183, HD 37017, HIP 26233, HR 1890, SAO 132317[14] | |
| Database references | |
| SIMBAD | data |
The binary nature of this system was suggested by A. Blaauw and T. S. van Albada in 1963.[11] It is a double-lined[13] spectroscopic binary with an orbital period of 18.6556 days and an eccentricity of 0.31.[16] The eccentricity is considered unusually large for such a close system.[13] It has been suspected of being an eclipsing binary or rotating ellipsoidal variable, and the primary is also am SX Arietis variable.[8]
The primary is a helium-strong, magnetic chemically peculiar star[17] with a stellar classification of B1.5 Vp.[6] It has a magnetic field strength of 7,700 G,[18] and the helium concentrations are located at the magnetic poles.[19] V1046 Orionis was found to be a variable star by L. A. Balona in 1997,[13] and is now classified as an SX Arietis variable.[8] 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.[13] Radio emission has been detected that varies with the rotation period.[19]
The secondary component has an estimated 4.5 times the mass of the Sun. The class has been estimated as type B6III-IV.[13]