VX Sagittarii

VX Sagittarii

A visual band light curve for VX Sagittarii, plotted from AAVSO data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 18h 08m 04.04831s[2]
Declination −22° 13′ 26.6327″[2]
Apparent magnitude (V) 6.5 - 14.0[3]
Characteristics
Evolutionary stage AGB, (possibly TŻO)[4]
Spectral type M4eIa - M10eIa[5]
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[3]
Astrometry
Radial velocity (Rv)+6.47±3.37[6] km/s
Proper motion (μ) RA: +0.36±0.76[6] mas/yr
Dec.: −2.92±0.78[6] mas/yr
Parallax (π)0.64 ± 0.04 mas[6]
Distance5,100 ± 300 ly
(1,560 ± 100 pc)
Details
Mass12[7] M☉
Radius1,356,[4] between 1,120 and 1,550[6], 1,350–1,940 (pulsation)[8], 1,480[9][a] R☉
Luminosity195000±62000[6] L☉
Temperature2,900[10] (near min), 3,200-3,400 (near max)[7], 2,400–3,300[8] K
Other designations
VX Sgr, HIP 88838, BD−22°4575, CD−22°12589, HD 165674, 2MASS J18080404-2213266, AAVSO 1802-22
Database references
SIMBADdata

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.[4]

  1. ^ Cite error: The named reference aavso was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference hipparcos was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  4. ^ a b c Tabernero, H. M.; Dorda, R.; Negueruela, I.; Marfil, E. (2021). "The nature of VX Sagitarii". Astronomy & Astrophysics. 646: A98. arXiv:2011.09184. doi:10.1051/0004-6361/202039236. S2CID 227013580.
  5. ^ Cite error: The named reference kiss was invoked but never defined (see the help page).
  6. ^ a b c d e f Cite error: The named reference xu2018 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference chiavassa was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Lockwood was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference wallstrom was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference gh was invoked but never defined (see the help page).


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