Theta1 Orionis D
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 35m 17.24645s |
| Declination | −05° 23′ 16.5707″ |
| Apparent magnitude (V) | 6.70 |
| Characteristics | |
| Spectral type | B1.5 Vp |
| U−B color index | −0.71 |
| B−V color index | +0.09 |
| Astrometry | |
| Radial velocity (Rv) | +32.4 km/s |
| Proper motion (μ) | RA: +1.822 mas/yr Dec.: _0.393 mas/yr |
| Parallax (π) | 2.2820±0.0207 mas |
| Distance | 1,430 ± 10 ly (438 ± 4 pc) |
| Absolute magnitude (MV) | −3.3 |
| Details | |
| Mass | 18±6 M☉ |
| Radius | 5.6±0.8 R☉ |
| Luminosity | 29,500 L☉ |
| Surface gravity (log g) | 4.2±0.1 cgs |
| Temperature | 32,000±1,000 K |
| Rotational velocity (v sin i) | 49.0±0.9 km/s |
| Age | 2.5±0.5 Myr |
| Other designations | |
| θ1 Orionis D, 41 Orionis D, HR 1896, HD 37023, HIP 26224, WDS J05353-0523D | |
| Database references | |
| SIMBAD | data |
Theta1 Orionis D (θ1 Orionis D) is a member of the Trapezium open cluster that lies within the Orion Nebula. It is a B class blue main sequence star with several faint companions.
θ1 Orionis consists of multiple components, primarily the four stars of the Trapezium cluster (A, B, C, and D) all within one arc-minute of each other. θ2 Orionis is a more distant grouping of three main stars plus several fainter companions, 1-2 arc-minutes from θ1.
θ1 D itself has a faint optical companion 1.4" away and a spectroscopic companion in a 40-day orbit. Infrared Optical Telescope Array observations suggest another companion at 18.6 mas.