V4381 Sagittarii, a white supergiant star in Sagittarius
V4381 Sagittarii is a white supergiant star in the constellation Sagittarius. At 5,199 light years away, it shines at an apparent visual magnitude of 6.58.
V4381 Sagittarii (HIP 88876)
V4381 Sagittarii is a white supergiant star in the constellation Sagittarius. At 5,199 light years away, it shines at an apparent visual magnitude of 6.58. It is moving through the Galaxy at a speed of 19.1 km/s relative to the Sun.
Sky position: RA 18h 8.6m, Dec -21° 27.0'
Common designations: V4381 Sagittarii, HD 165784, HIP 88876, Gaia DR3 4069845455625999872
V4381 Sagittarii has the spectral type A2Iab. 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 I marks it as a supergiant, among the most luminous and largest stars known.
How to find V4381 Sagittarii in the sky
V4381 Sagittarii lies in Sagittarius. With a declination of -21° 27.0', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 69° N. It is just beyond naked-eye visibility; binoculars will show it easily. It is highest in the sky at local midnight around July, which makes the weeks around that month the best time to observe it.
Tabulated data for V4381 Sagittarii
Astrometry and spectroscopy
| Right Ascension (J2000) | 272.16077516° (18h 8.6m) |
| Declination (J2000) | -21.44955986° (-21° 27.0') |
| Galactic Longitude | 9.08625368° |
| Galactic Latitude | -0.74297793° |
| Proper motion RA | -0.70 mas/yr |
| Proper motion Dec | -1.40 mas/yr |
| Parallax | 0.63 ± 0.04 mas |
| Spectral Type | A2Iab |
| Radial Velocity | -15.08 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 7.70 | -3.31 |
| B | 7.42 | -3.59 |
| V | 6.58 | -4.43 |
| R | 7.22 | -3.79 |
| J | 4.64 | -6.37 |
| H | 4.17 | -6.84 |
| K | 4.15 | -6.86 |
Colour index B-V: +0.84
Derivations
- Heliocentric distance: 1,594.13 pc (5,199 light years) (5.9% margin of error)
- Absolute visual magnitude: -4.43
- Transverse velocity: 11.8 km/s
- Space velocity relative to the Sun: 19.1 km/s
- Galactic position (X, Y, Z): 1574.0 pc, 251.7 pc, -20.7 pc
- Galactic velocity (U, V, W): -13.0 km/s, -14.0 km/s, -0.3 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.