22 Orionis is a binary star[12] in the equatorial constellation of Orion. It has the Bayer designation o Orionis, while 22 Orionis is the Flamsteed designation. This system is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.74.[2] It is located approximately 1,100 light years away from the Sun based on parallax.[1] The system is moving further from the Earth with a heliocentric radial velocity of +28.80[5]

22 Orionis

Location of 22 Orionis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Orion
Right ascension	05h 21m 45.74861s[1]
Declination	0° 22′ 56.9105″[1]
Apparent magnitude (V)	4.74[2]
Characteristics
Spectral type	B2 IV-V[3][4]
U−B color index	-0.79[2]
B−V color index	-0.16[2]
Astrometry
Radial velocity (Rv)	+28.80[5] km/s
Proper motion (μ)	RA: −1.320[1] mas/yr Dec.: +3.457[1] mas/yr
Parallax (π)	2.8672 ± 0.3512 mas[1]
Distance	approx. 1,100 ly (approx. 350 pc)
Absolute magnitude (MV)	−2.98[6]
Orbit[7]
Period (P)	293 days
Eccentricity (e)	0.15
Periastron epoch (T)	2,442,175 JD
Argument of periastron (ω) (secondary)	234°
Semi-amplitude (K1) (primary)	4.1 km/s
Details
22 Ori A
Mass	9.0[8] M☉
Luminosity	741[9] L☉
Surface gravity (log g)	3.56[10] cgs
Temperature	19,953[9] K
Metallicity [Fe/H]	−0.06[10] dex
Rotational velocity (v sin i)	9[9] km/s
Age	18.5[8] Myr
Other designations
o Orionis, 22 Ori, NSV 16291, BD−00°930, FK5 1147, GC 6579, HD 35039, HIP 25044, HR 1765, SAO 132028[11]
Database references
SIMBAD	data

This is a single-lined spectroscopic binary with an orbital period of 293 days and an eccentricity of 0.15.[7] The visible member, component A, has a stellar classification of B2 IV-V,[3][4] matching a B-type star with a luminosity class that displays mixed traits of a main sequence star and a subgiant. It is a suspected Beta Cephei variable[13] or a slowly pulsating B star.[14] The star has nine[8] times the mass of the Sun and is radiating 741 times the Sun's luminosity[9] from its photosphere at an effective temperature of 19,953 K.[9]

References