Phi Andromedae

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**φ Andromedae**
Observation data Epoch J2000

Constellation (pronunciation)	Andromeda
Right ascension	01h 09m 30.1255s
Declination	+47° 14' 30.453"'
Apparent magnitude (V)	4.252
Characteristics
Spectral type	B7V
U-B color index	-0.34
B-V color index	-0.07
Variable type	None
Astrometry
Radial velocity (R_v)	-0.1 km/s
Proper motion (μ)	RA: 3.81 mas/yr Dec.: -13.02 mas/yr
Parallax (π)	4.43 ± 0.80 mas
Distance	approx. 700 ly (approx. 230 pc)
Absolute magnitude (M_V)	4.197
Details
Mass	18 M_☉
Radius	7 R_☉
Surface gravity (log g)	?
Luminosity	20.000 L_☉
Temperature	10.000–30.000 K
Metallicity	?
Rotation	?
Age	? years
Visual binary orbit
Companion	φ Andromedae B
Period (P)	371.6 yr
Semimajor axis (a)	0.447"
Eccentricity (e)	0.21
Inclination (i)	131°
Longitude of the node (Ω)	148.2°
Periastron epoch (T)	1889.9
Visual binary orbit
Companion	φ Andromedae C
Semimajor axis (a)	10"
Inclination (i)	224°
Visual binary orbit
Companion	φ Andromedae D
Semimajor axis (a)	27.7"
Inclination (i)	64°
Other designations
42 Andromedae, HR 335,HD 6811, BD+46°275, HIP 5434, SAO 36972, GC 1394, ADS 940, CCDM 01095+4715.
Database references
SIMBAD	data
Database references
SIMBAD	data

Phi Andromedae is a binary star system near the border of the constellation of Andromeda, approximately 735 light years from Earth. It has the traditional name Keun Nan Mun, which it shares with χ Andromedae. This name derives from Mandarin 軍南門 jūnnánmén, meaning 'the south gate of the camp'.

The primary component, Phi Andromedae A, is a blue-white B-type subgiant with an apparent magnitude of +4.6. The companion star, Phi Andromedae B, is a blue-white B-type main sequence dwarf with an apparent magnitude of 5.6. The two stars are separated by 0.64 arcseconds and have an orbital period of 371.6 years. The combined brightness of the system is +4.26 magnitudes.