12 Persei

12 Persei (12 Per) is a double-lined spectroscopic binary star system in the northern constellation Perseus. Its combined apparent magnitude is 4.94,^[2] which means it can be viewed with the naked eye. Based upon parallax measurements, this system is about 79 light years away from the Sun.^[1]

12 Persei

Location of 12 Persei (circled)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Perseus
Right ascension	02h 42m 14.91569s[1]
Declination	+40° 11′ 38.1898″[1]
Apparent magnitude (V)	4.94[2]
Characteristics
Spectral type	F9 V[3]
U−B color index	+0.08[2]
B−V color index	+0.56[2]
Astrometry
Radial velocity (Rv)	5.20[4] km/s
Proper motion (μ)	RA: −17.20[1] mas/yr Dec.: −183.30[1] mas/yr
Parallax (π)	41.34±0.43 mas[1]
Distance	78.9 ± 0.8 ly (24.2 ± 0.3 pc)
Orbit
Period (P)	330.98[5] d
Semi-major axis (a)	53.18[6] mas
Eccentricity (e)	0.663[5]
Inclination (i)	127.17[6]°
Details
12 Per A
Mass	1.382±0.019[5] M☉
Radius	1.55[5] R☉
Luminosity	3.02[5] L☉
Surface gravity (log g)	4.20±0.10[5] cgs
Temperature	6195±200[5] K
Metallicity [Fe/H]	≥0.35[5] dex
Rotational velocity (v sin i)	13[7] km/s
Age	1.12[5] Gyr
12 Per B
Mass	1.240±0.017[5] M☉
Radius	1.31[5] R☉
Luminosity	1.86[5] L☉
Surface gravity (log g)	4.30±0.10[5] cgs
Temperature	6000±200[5] K
Other designations
12 Per, BD+39° 610, FK5 2187, GJ 105.6 АВ, HD 16739, HIP 12623, HR 788, SAO 55793.[8]
Database references
SIMBAD	data

The magnitude difference between the two components is estimated to be 0.51. Based upon this, the primary has a mass around 138% of the Sun, 155% of the Sun's radius, and shines with three times the Sun's luminosity. The smaller secondary component is also larger than the Sun, with 124% of the Sun's mass, 131% of the radius of the Sun, and has 186% of the Sun's luminosity.^[5] The stellar classification of the primary is F9 V,^[3] which suggests it is an F-type main sequence star. The pair have an estimated age of just over a billion years.^[5]

The pair orbit each other with a period of 331 days and an eccentricity of 0.663.^[5] The semimajor axis of their orbit is 1.27 AU, which means the inner stability radius for a hypothetical planet orbiting the pair would be at 4.35 AU. This lies outside the habitability zone for this system.^[9]