VX Sagittarii
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 08m 04.04831s |
| Declination | −22° 13′ 26.6327″ |
| Apparent magnitude (V) | 6.5 - 14.0 |
| Characteristics | |
| Evolutionary stage | AGB |
| Spectral type | M4eIa - M10eIa |
| Apparent magnitude (U) | 11.72 |
| Apparent magnitude (B) | 9.41 |
| Apparent magnitude (V) | 6.52 |
| Apparent magnitude (I) | 2.11 |
| Apparent magnitude (J) | 1.23 |
| Apparent magnitude (H) | 0.13 |
| Apparent magnitude (K) | −0.50 |
| Apparent magnitude (L) | −1.61 |
| Variable type | SRc |
| Astrometry | |
| Radial velocity (Rv) | +6.47±3.37 km/s |
| Proper motion (μ) | RA: +0.36±0.76 mas/yr Dec.: −2.92±0.78 mas/yr |
| Parallax (π) | 0.64±0.04 mas |
| Distance | 5,100 ± 300 ly (1,560 ± 100 pc) |
| Details | |
| Mass | 10 to 12 M☉ |
| Radius | 1,360+250 −230, between 1,120 and 1,550, 1,350–1,940 (pulsation), 1,480 R☉ |
| Luminosity | 195,000±62,000 L☉ |
| Temperature | 2,900 (near min), 3,200-3,400 (near max), 2,400–3,300 K |
| Other designations | |
| VX Sgr, HIP 88838, BD−22°4575, CD−22°12589, HD 165674, 2MASS J18080404-2213266, AAVSO 1802-22 | |
| Database references | |
| SIMBAD | data |
VX Sagittarii is an asymptotic giant branch star located more than 1.5 kiloparsec away from the Sun in the constellation of Sagittarius. It is a pulsating variable star with an unusually large magnitude range. It is one of the largest stars discovered, with a radius varying between 1,350 and 1,940 solar radii (940,000,000 and 1.35×109 km; 6.3 and 9.0 au). It is the most luminous known AGB star, at bolometric magnitude −8.6, which is brighter than the theoretical limit at −8.0.