58 Persei

This article is about e Persei and is not to be confused with ε (epsilon) Persei.

58 Persei is a binary^[3] and possibly a triple^[13] star system in the northern constellation of Perseus. It has the Bayer designation e Persei, while 58 Persei is the Flamsteed designation. This system is visible to the naked eye as a faint point of light with an apparent visual magnitude of 4.26.^[2] It is approximately 800 light years away from the Sun based on parallax,^[1] and is drifting further away with a radial velocity of +10 km/s.^[4]

58 Persei

Location of 58 Persei (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Perseus
Right ascension	04h 36m 41.43017s[1]
Declination	+41° 15′ 53.3213″[1]
Apparent magnitude (V)	4.26[2]
Characteristics
Spectral type	K1II + B7V[3]
U−B color index	+0.81[2]
B−V color index	+1.24[2]
Astrometry
Radial velocity (Rv)	+9.80[4] km/s
Proper motion (μ)	RA: −4.56[1] mas/yr Dec.: −17.84[1] mas/yr
Parallax (π)	4.09±0.38 mas[1]
Distance	800 ± 70 ly (240 ± 20 pc)
Absolute magnitude (MV)	-2.67[5]
Orbit[6]
Primary	58 Persei A
Companion	58 Persei B
Period (P)	28.8 yr
Semi-major axis (a)	0.051″
Eccentricity (e)	0.64
Inclination (i)	81°
Longitude of the node (Ω)	237°
Periastron epoch (T)	1978.65
Argument of periastron (ω) (secondary)	191°
Details
58 Per A
Mass	6.8±0.2[7] M☉
Radius	86.7+4.6 −5.1[8] R☉
Luminosity	1,731±323[9] L☉
Surface gravity (log g)	2.21[10] cgs
Temperature	4,500[9] K
Metallicity [Fe/H]	−0.20[5] dex
Rotational velocity (v sin i)	11.0[11] km/s
Age	50.1±6.8[7] Myr
Other designations
Boss 1074, 58 Per, BD+40°1000, FK5 2338, GC 5609, HD 29094–95, HIP 21476, HR 1454, SAO 39639, CCDM J04367+4116A[12]
Database references
SIMBAD	data

This is a single-lined spectroscopic binary system with an orbital period of 28.7 years and an eccentricity of 0.65.^[14] The primary member, designated component A, is an orange-hued (K–type) bright giant with a stellar classification of K1II.^[3] The star is around 50 million years old^[7] with 6.8 times the mass of the Sun.^[7] Having exhausted the supply of hydrogen at its core, it has expanded to roughly 87 times the Sun's radius.^[8] It is radiating 1,731 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,500 K.^[9]

The secondary, component B, appears to be a B-type main-sequence star with a stellar classification of B7V.^[3] It is a suspected binary of unknown period with component masses of 3.3 and 1.2 times the mass of the Sun.^[13]