Kappa Pegasi

Kappa Pegasi (κ Peg, κ Pegasi) is a triple star system in the constellation Pegasus. It has an apparent brightness of +4.13 magnitude and belongs to the spectral class F5IV; a subgiant star. No proper name is associated to this star.^[8]

Kappa Pegasi

Location of Kappa Pegasi (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Pegasus
Right ascension	21h 44m 38.7344s[1]
Declination	+25° 38′ 42.128″[1]
Apparent magnitude (V)	4.159
Characteristics
Spectral type	F5IV
U−B color index	+0.03[2]
B−V color index	+0.44[2]
Astrometry
Radial velocity (Rv)	−8.1 km/s
Proper motion (μ)	RA: 46.66[1] mas/yr Dec.: 13.47[1] mas/yr
Parallax (π)	28.90±0.18 mas[3]
Distance	112.9 ± 0.7 ly (34.6 ± 0.2 pc)
Orbit[3]
Primary	κ Peg A
Companion	κ Peg B
Period (P)	4227.05 ± 0.55 d
Semi-major axis (a)	8.139 ± 0.062 AU
Eccentricity (e)	0.3180 ± 0.0015
Inclination (i)	107.872 ± 0.028°
Longitude of the node (Ω)	109.140 ± 0.057°
Periastron epoch (T)	2452398.0 ± 2.0
Argument of periastron (ω) (secondary)	304.14 ± 0.21°
Orbit[3]
Primary	κ Peg Ba
Companion	κ Peg Bb
Period (P)	5.9714971 ± 0.0000013
Semi-major axis (a)	0.08715 ± 0.00090 AU
Eccentricity (e)	0.0073 ± 0.0013
Inclination (i)	124.9 ± 3.7°
Longitude of the node (Ω)	359.1 ± 5.9°
Periastron epoch (T)	2452402.225 ± 0.097
Argument of periastron (ω) (secondary)	359.1 ± 5.9°
Details[4]
A
Mass	1.391±0.044 M☉
Surface gravity (log g)	3.00[5] cgs
Temperature	6,579[5] K
Metallicity [Fe/H]	-0.37 dex
Rotational velocity (v sin i)	35[6] km/s
Ba
Mass	1.616±0.049 M☉
Bb
Mass	0.835±0.026 M☉
Other designations
10 Pegasi, HR 8315, BD+24 4463, HD 206901, SAO 89949, HIP 107354.[7]
Database references
SIMBAD	data

This system consists of two components, designated Kappa Pegasi A and B, that are separated by an angular distance of 0.235 arcseconds. The binary nature of this pair was discovered by Sherburne W. Burnham in 1880. They orbit around each other every 11.6 years with a semimajor axis of 0.4 arcseconds. The brighter member of the pair, Kappa Pegasi B, is actually a spectroscopic binary, with the components designated Kappa Pegasi Ba and Kappa Pegasi Bb. They orbit about each other every six days. There is a fourth component, Kappa Pegasi C, which may be an optical companion.^[3]