25 Vulpeculae

25 Vulpeculae is a single^[2] star in the northern constellation of Vulpecula, located roughly 1,170 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.50^[2] This object is moving closer to the Earth with a heliocentric radial velocity of −11 km/s.^[5]

25 Vulpeculae

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Vulpecula
Right ascension	20h 22m 03.43076s[1]
Declination	+24° 26′ 45.9526″[1]
Apparent magnitude (V)	5.50[2]
Characteristics
Spectral type	B6 IVe[3][4]
B−V color index	−0.09±0.02[4]
Astrometry
Radial velocity (Rv)	−11.0±3.6[5] km/s
Proper motion (μ)	RA: +0.605[1] mas/yr Dec.: −5.732[1] mas/yr
Parallax (π)	2.7932±0.1493 mas[1]
Distance	1,170 ± 60 ly (360 ± 20 pc)
Absolute magnitude (MV)	−1.88[4]
Details
Mass	7±1[6] M☉
Radius	11±1[6] R☉
Luminosity (bolometric)	1,345+215 −184[7] L☉
Surface gravity (log g)	3.52±0.21[7] cgs
Temperature	13,170±330[7] K
Rotational velocity (v sin i)	160±14[7] km/s
Other designations
25 Vul, BD+23°3986, HD 193911, HIP 100435, HR 7789, SAO 88580[8]
Database references
SIMBAD	data

This is a Be star with a stellar classification of B6 IVe,^[3] matching the spectrum of an aging subgiant with a circumstellar disk of ionized gas. Cowley (1972) had it rated as a more evolved giant star with a class of B8 IIIn,^[9] where the 'n' notation indicates "nebulous" lines due to rapid rotation. It has a high rate of spin, showing a projected rotational velocity of 160 km/s.^[7] The star has 7 times the mass of the Sun and 11 times the Sun's radius.^[6] It is radiating 1,345 times the luminosity of the Sun from its photosphere at an effective temperature of 13,170 K.^[7]