20 Vulpeculae

20 Vulpeculae is single^[5] star located around 1,170^[1] light years away in the northern constellation of Vulpecula.^[8] It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.91.^[2] The object is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.^[2]

20 Vulpeculae

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Vulpecula
Right ascension	20h 12m 00.70176s[1]
Declination	+26° 28′ 43.6989″[1]
Apparent magnitude (V)	5.91[2]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	B7 Ve[4][5]
B−V color index	−0.107±0.003[2]
Astrometry
Radial velocity (Rv)	−22.0±4.3[2] km/s
Proper motion (μ)	RA: +4.096[1] mas/yr Dec.: −9.524[1] mas/yr
Parallax (π)	2.7904±0.0726 mas[1]
Distance	1,170 ± 30 ly (358 ± 9 pc)
Absolute magnitude (MV)	−2.13[2]
Details
Mass	4.02±0.14[3] M☉
Radius	3.0[6] R☉
Luminosity	460+88 −74[3] L☉
Surface gravity (log g)	2.90[7] cgs
Temperature	12,050+168 −165[3] K
Rotational velocity (v sin i)	236[3] km/s
Other designations
20 Vul, BD+26°3828, HD 192044, HIP 99531, HR 7719, SAO 88339[8]
Database references
SIMBAD	data

This is a Be star with a stellar classification of B7 Ve.^[4] It is spinning rapidly with a projected rotational velocity of 236 km/s (compared to a critical velocity of 332 km/s)^[3] and has an estimated polar inclination of 71.1°.^[9] The star has four times the mass of the Sun and is radiating around 460 times the Sun's luminosity from its photosphere at an effective temperature of 12,050 K.^[3]