13 Andromedae

13 Andromedae, abbreviated 13 And, is a single,^[10] blue-white hued variable star^[4] in the northern constellation of Andromeda. 13 Andromedae is the Flamsteed designation, while it bears the variable star designation V388 Andromedae. With a typical apparent visual magnitude of around 5.75,^[2] it is dimly visible to the naked eye under good seeing conditions. The distance to this star can be directly estimated from its annual parallax shift of 10.9 mas,^[1] yielding a range of 300 light years. At that distance, its brightness is diminished by an extinction of 0.13 magnitude due to interstellar dust.^[6] The star is moving closer to the Earth with a heliocentric radial velocity of −8 km/s.^[5]

13 Andromedae

Location of 13 Andromedae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda
Right ascension	23h 27m 07.40s[1]
Declination	+42° 54′ 43.2″[1]
Apparent magnitude (V)	5.75[2]
Characteristics
Spectral type	B9 III or B9 Mn[3]
B−V color index	−0.007±0.004[2]
Variable type	α2 CVn[4]
Astrometry
Radial velocity (Rv)	−8.1±1.6[5] km/s
Proper motion (μ)	RA: 87.05[1] mas/yr Dec.: 16.54[1] mas/yr
Parallax (π)	10.87±0.30 mas[1]
Distance	300 ± 8 ly (92 ± 3 pc)
Absolute magnitude (MV)	0.98[6]
Details
Luminosity	42.89[2] L☉
Rotational velocity (v sin i)	75[7] km/s
Age	345[6] Myr
Other designations
13 And, V388 Andromedae, BD+42°4672, HD 220885, HIP 115755, HR 8913, SAO 53039, PPM 64250[8]
Database references
SIMBAD	data

The visual band light curve of 13 Andromedae, adapted from Adelman (2005)^[9]

The variability of 13 Andromedae was first detected in Hipparcos satellite data, and it received its variable star designation in 1999.^[11][12]

This is a magnetic chemically peculiar star that has been assigned stellar classifications of B9 III or B9 Mn.^[3] It is a variable star of the Alpha² Canum Venaticorum type, ranging in magnitude from 5.73 down to 5.77^[4] with a period of 1.47946 days.^[3] The star has a high rate of spin, showing a projected rotational velocity of 75 km/s.^[7] 13 Andromedae is around 345^[6] million years old and shines with 43^[2] times the Sun's luminosity.