Alpha Sextantis, a white giant star in Sextans
Alpha Sextantis is a white giant star in the constellation Sextans. At 426 light years away, it shines at an apparent visual magnitude of 4.49.
Alpha Sextantis (HIP 49641)
Alpha Sextantis is a white giant star in the constellation Sextans. At 426 light years away, it shines at an apparent visual magnitude of 4.49. It is moving through the Galaxy at a speed of 12.0 km/s relative to the Sun.
Sky position: RA 10h 7.9m, Dec -0° 22.3'
Common designations: Alpha Sextantis, 15 Sextantis, HR 3981, HD 87887, HIP 49641, Gaia DR3 3830286576563947136
Alpha Sextantis has the spectral type A0III. A-type stars are white stars with surface temperatures of roughly 7,500 to 10,000 K. Their spectra are dominated by strong hydrogen lines, and many of them rotate rapidly. Its luminosity class III marks it as a giant: an evolved star that has left the main sequence and swollen to many times its original size.
How to find Alpha Sextantis in the sky
Alpha Sextantis lies in Sextans. With a declination of -0° 22.3', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 90° N. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around March, which makes the weeks around that month the best time to observe it.
Tabulated data for Alpha Sextantis
Astrometry and spectroscopy
| Right Ascension (J2000) | 151.98451570° (10h 7.9m) |
| Declination (J2000) | -0.37167037° (-0° 22.3') |
| Galactic Longitude | 241.10940457° |
| Galactic Latitude | 42.06576035° |
| Proper motion RA | -13.06 mas/yr |
| Proper motion Dec | -9.67 mas/yr |
| Parallax | 7.66 ± 0.37 mas |
| Spectral Type | A0III |
| Radial Velocity | 6.47 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 4.45 | -1.13 |
| V | 4.49 | -1.09 |
| J | 4.65 | -0.93 |
| H | 4.60 | -0.98 |
| K | 4.45 | -1.13 |
Colour index B-V: -0.04
Derivations
- Heliocentric distance: 130.58 pc (426 light years) (4.9% margin of error)
- Absolute visual magnitude: -1.09
- Transverse velocity: 10.1 km/s
- Space velocity relative to the Sun: 12.0 km/s
- Galactic position (X, Y, Z): -46.8 pc, -84.9 pc, 87.5 pc
- Galactic velocity (U, V, W): -5.9 km/s, -9.9 km/s, -3.1 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.