AS 314

AS 314, also known as V452 Scuti, is a protoplanetary nebula^[4] once believed to be a white hypergiant star or luminous blue variable located in the constellation of Scutum. It has an apparent magnitude of 9.85 and can be seen with small telescopes.

V452 Scuti

A visual band light curve for V452 Scuti, plotted from OMC data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Scutum
Right ascension	18h 39m 26.10226s[2]
Declination	−13° 50′ 47.1597″[2]
Apparent magnitude (V)	9.85[3]
Characteristics
Spectral type	Protoplanetary nebula[4]
U−B color index	+0.12[3]
B−V color index	+0.89[3]
Variable type	α Cyg?[5]
Astrometry
Radial velocity (Rv)	−77±8[2] km/s
Proper motion (μ)	RA: −4.416[2] mas/yr Dec.: −6.241[2] mas/yr
Parallax (π)	0.5853±0.0141 mas[2]
Distance	5,600 ± 100 ly (1,710 ± 40 pc)
Details
Luminosity	3,200[4] L☉
Temperature	10,200[6] K
Other designations
V452 Sct, BD−13°5061, HIP 91477, 2MASS J18392610-1350470
Database references
SIMBAD	data

Characteristics

AS 314 was found to be a variable star in 1996, when the Hipparcos data was analyzed. For that reason it was given the variable star designation V452 Scuti, in 1999.^[7]

AS 314 was poorly studied until the year 2000, when Miroshnichenko et al. incorrectly estimated a distance for this star of around 10 kiloparsecs (32,600 light years), a luminosity 160,000 times that of Sun (L_☉), a radius 200 times the solar radius (R_☉), and an initial mass of 20 solar masses (M_☉). It was also estimated to be losing 2 × 10⁻⁵ M_☉ each year (in other words, 1 M_☉ every 50,000 years) through a very strong stellar wind.^[8]

AS 314 has an infrared excess, suggesting that it is shrouded in a circumstellar envelope of dust.^[8][9] However, it has not been classified as a bona fide luminous blue variable, but as a candidate.^[10]

The Hipparcos parallax and proper motions are large and imply a much closer, and hence less luminous, star.^[11] The Hipparcos measurement was later confirmed by the Gaia mission,^[2] reclassifying AS 314 as post-AGB star.^[4]