Theta Crateris, a blue-white main-sequence star in Crater
Theta Crateris is a blue-white main-sequence star in the constellation Crater. At 301 light years away, it shines at an apparent visual magnitude of 4.67.
Theta Crateris (HIP 56633)
Theta Crateris is a blue-white main-sequence star in the constellation Crater. At 301 light years away, it shines at an apparent visual magnitude of 4.67. It is moving through the Galaxy at a speed of 26.6 km/s relative to the Sun.
Sky position: RA 11h 36.7m, Dec -9° 48.1'
Common designations: Theta Crateris, 21 Crateris, HR 4468, HD 100889, Gaia DR3 3587107658569000960, HIP 56633
Theta Crateris has the spectral type B9.5V. 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 Crateris in the sky
Theta Crateris lies in Crater. With a declination of -9° 48.1', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 80° N. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around April, which makes the weeks around that month the best time to observe it.
Tabulated data for Theta Crateris
Astrometry and spectroscopy
| Right Ascension (J2000) | 174.17045502° (11h 36.7m) |
| Declination (J2000) | -9.80222270° (-9° 48.1') |
| Galactic Longitude | 274.24938360° |
| Galactic Latitude | 48.86160456° |
| Proper motion RA | -59.99 mas/yr |
| Proper motion Dec | 3.96 mas/yr |
| Parallax | 10.85 ± 0.19 mas |
| Spectral Type | B9.5V |
| Radial Velocity | -4.24 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 4.60 | -0.22 |
| V | 4.67 | -0.15 |
| J | 4.79 | -0.03 |
| H | 4.84 | 0.02 |
| K | 4.78 | -0.04 |
Colour index B-V: -0.07
Derivations
- Heliocentric distance: 92.16 pc (301 light years) (1.7% margin of error)
- Absolute visual magnitude: -0.15
- Transverse velocity: 26.3 km/s
- Space velocity relative to the Sun: 26.6 km/s
- Galactic position (X, Y, Z): 4.5 pc, -60.5 pc, 69.4 pc
- Galactic velocity (U, V, W): -24.0 km/s, -6.4 km/s, -9.6 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.