33 Pegasi

33 Pegasi is the Flamsteed designation for a visual binary star in the northern constellation of Pegasus. It has an apparent visual magnitude of 6.2,^[2] placing it near the limit of naked eye visibility. Measurements show an annual parallax shift of 0.0298125″,^[1] which is equivalent to a distance of 109 ly (33 pc) from the Sun. It is drifting further away with a radial velocity of 24 km/s.^[2]

33 Pegasi

Observation data Epoch J2000      Equinox J2000
Constellation	Pegasus
Right ascension	22h 23m 39.565s[1]
Declination	20° 50′ 53.84″[1]
Apparent magnitude (V)	6.203[2] (6.391 + 9.287)[3]
Characteristics
Spectral type	F7 V[4]
B−V color index	0.518±0.004[5]
Astrometry
Radial velocity (Rv)	23.8±0.4[2] km/s
Proper motion (μ)	RA: +333.057 mas/yr[1] Dec.: −10.827 mas/yr[1]
Parallax (π)	29.8125±0.0436 mas[1]
Distance	109.4 ± 0.2 ly (33.54 ± 0.05 pc)
Absolute magnitude (MV)	3.55[2]
Details
33 Peg A
Mass	1.28[6] M☉
Radius	1.29+0.15 −0.14[7] R☉
Luminosity	2.850+0.007 −0.008[7] L☉
Surface gravity (log g)	4.29[8] cgs
Temperature	6,169[9] K
Metallicity [Fe/H]	–0.18[9] dex
Rotational velocity (v sin i)	6[2] km/s
Age	4.1[9] Gyr
33 Peg B
Mass	0.80[6] M☉
Other designations
33 Peg, BD–16 4196, HD 212395, HIP 110548, HR 8532, SAO 90462[10]
Database references
SIMBAD	data

The primary component of this system is a main sequence star with a visual magnitude of 6.4^[3] and a stellar classification of F7 V.^[4] It is nearly as old as the Sun with an estimated age of 4.1 billion years, but has a lower abundance of elements other than hydrogen and helium. The star has 1.3 times the mass^[6] and radius^[7] of the Sun. The stellar atmosphere has an effective temperature of 6,169 K,^[9] giving it the yellow-white glow of an F-type star.^[11]

A faint, magnitude 9.3 companion star is located at an angular separation of 0.420 arc seconds along a position angle of 0.0°.^[3] The pair have a projected separation of 15.6 AU^[6] with an orbital period of about 250 years.^[12]