22 Scorpii

This article is about i Scorpii and is not to be confused with ι Scorpii.

22 Scorpii (i Scorpii) is a single^[8] star in the southern zodiac constellation of Scorpius, about one degree from Antares. It is faintly visible to the naked eye with an apparent visual magnitude of 4.78.^[3] The distance to this star is estimated to be around 411 light years, as derived from its annual parallax shift of 7.9±0.2 mas. The star is embedded in, or adjacent to, the diffuse nebulous cloud IC 4605 located in the western regions of the Rho Ophiuchi cloud complex.^[9]

22 Scorpii in the IC 4605 reflection nebula, one of a collection of diffuse and dark nebulae in the Rho Ophiuchi cloud complex

22 Scorpii

Observation data Epoch J2000      Equinox J2000
Constellation	Scorpius[1]
Right ascension	16h 30m 12.47527s[2]
Declination	−25° 06′ 54.7966″[2]
Apparent magnitude (V)	4.78[3]
Characteristics
Evolutionary stage	main sequence[2]
Spectral type	B3 V[4]
Astrometry
Proper motion (μ)	RA: −4.192[2] mas/yr Dec.: −26.975[2] mas/yr
Parallax (π)	7.9402±0.1848 mas[2]
Distance	411 ± 10 ly (126 ± 3 pc)
Absolute magnitude (MV)	−0.72[1]
Details
Mass	4.4[5] M☉
Radius	3.4[2] R☉
Luminosity	601[5] L☉
Surface gravity (log g)	4.5[6] cgs
Temperature	16,683[5] K
Metallicity [Fe/H]	0.66[2] dex
Rotational velocity (v sin i)	169±4[3] km/s
Age	8[6] Myr
Other designations
i Sco, 22 Sco, CD−24°12695, HD 148605, HIP 80815, HR 6141, SAO 184429[7]
Database references
SIMBAD	data

22 Scorpii is a B-type main-sequence star with a stellar classification of B3 V.^[4] It is ten million years old^[10] and has a high rate of spin with a projected rotational velocity of 169 km/s.^[3] The star has about 4.4 times the mass of the Sun and is radiating 601 times the Sun's luminosity from its photosphere at an effective temperature of 16,683 K.^[3]