Theta-1 Orionis D, a blue-white main-sequence star in Orion
Theta-1 Orionis D is a blue-white main-sequence star in the constellation Orion. At 1,429 light years away, it shines at an apparent visual magnitude of 6.70.
Theta-1 Orionis D (HIP 26224)
Theta-1 Orionis D is a blue-white main-sequence star in the constellation Orion. At 1,429 light years away, it shines at an apparent visual magnitude of 6.70. It is moving through the Galaxy at a speed of 32.6 km/s relative to the Sun.
Sky position: RA 5h 35.3m, Dec -5° 23.3'
Common designations: Theta-1 Orionis D, 41 Orionis, Theta-1 Orionis, HR 1896, HD 37023, HIP 26224, Gaia DR3 3017364063330465152
Theta-1 Orionis D has the spectral type B1.5Vp. B-type stars are hot (about 10,000 to 30,000 K), luminous and blue-white. They are massive, short-lived stars, typically only tens of millions of years old, and are common in young clusters and OB associations. Its luminosity class V means it is a main-sequence (dwarf) star, still fusing hydrogen into helium in its core like the Sun.
How to find Theta-1 Orionis D in the sky
Theta-1 Orionis D lies in Orion. With a declination of -5° 23.3', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 85° N. It is just beyond naked-eye visibility; binoculars will show it easily. It is highest in the sky at local midnight around January, which makes the weeks around that month the best time to observe it.
Tabulated data for Theta-1 Orionis D
Astrometry and spectroscopy
| Right Ascension (J2000) | 83.82190603° (5h 35.3m) |
| Declination (J2000) | -5.38793632° (-5° 23.3') |
| Galactic Longitude | 209.01065966° |
| Galactic Latitude | -19.38032283° |
| Proper motion RA | 1.82 mas/yr |
| Proper motion Dec | 0.39 mas/yr |
| Parallax | 2.28 ± 0.03 mas |
| Spectral Type | B1.5Vp |
| Radial Velocity | 32.40 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 6.08 | -2.13 |
| B | 6.79 | -1.42 |
| V | 6.70 | -1.51 |
| R | 6.40 | -1.81 |
| I | 6.20 | -2.01 |
| J | 6.01 | -2.20 |
| H | 5.89 | -2.32 |
| K | 5.75 | -2.46 |
Colour index B-V: +0.09
Derivations
- Heliocentric distance: 438.21 pc (1,429 light years) (1.5% margin of error)
- Absolute visual magnitude: -1.51
- Transverse velocity: 3.9 km/s
- Space velocity relative to the Sun: 32.6 km/s
- Galactic position (X, Y, Z): -361.5 pc, -200.5 pc, -145.4 pc
- Galactic velocity (U, V, W): -27.3 km/s, -16.3 km/s, -7.2 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.