HD 37017
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. It is located at a distance of approximately 1,230 light years based on parallax, and is drifting further away with a radial velocity of +32 km/s. The system is part of star cluster NGC 1981.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 35m 21.86770s |
| Declination | −04° 29′ 39.0409″ |
| Apparent magnitude (V) | 6.553 |
| Characteristics | |
| Evolutionary stage | B2/3V (B1.5 Vp He strong) |
| U−B color index | −0.79 |
| B−V color index | −0.14 |
| Variable type | SX Ari |
| Astrometry | |
| Radial velocity (Rv) | +32±2 km/s |
| Proper motion (μ) | RA: 1.88±0.09 mas/yr Dec.: 1.20±0.14 mas/yr |
| Parallax (π) | 2.643 ± 0.075 mas |
| Distance | 1,230 ± 40 ly (380 ± 10 pc) |
| Orbit | |
| 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 M☉ |
| Luminosity | 3,754 L☉ |
| Temperature | 23,700 K |
| Rotation | 0.901 d |
| Rotational velocity (v sin i) | 165 km/s |
| B | |
| Mass | 4.5 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The binary nature of this system was suggested by A. Blaauw and T. S. van Albada in 1963. It is a double-lined spectroscopic binary with an orbital period of 18.6556 days and an eccentricity of 0.31. The eccentricity is considered unusually large for such a close system. It forms a suspected eclipsing binary that ranges in brightness from 6.54 down to 6.58.
The primary is a helium-strong, magnetic chemically peculiar star with a stellar classification of B1.5 Vp. It has a magnetic field strength of 7,700 G, and the helium concentrations are located at the magnetic poles. V1046 Orionis was found to be a variable star by L. A. Balona in 1997, and is now classified as an SX Arietis variable. 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. Radio emission has been detected that varies with the rotation period.
The secondary component has an estimated 4.5 times the mass of the Sun. The class has been estimated as type B6III-IV.