22 Tauri

22 Tauri is a component of the Asterope double star in the Pleiades open cluster. 22 Tauri is the stars' Flamsteed designation. It is situated near the ecliptic and thus is subject to lunar occultation.^[9] The star has an apparent visual magnitude of 6.43,^[2] which is near the lower threshold of visibility to the naked eye. Anybody attempting to view the object is likely to instead see the Asterope pair as a single elongated form of magnitude 5.6.^[10] Based upon an annual parallax shift of 7.35 mas,^[1] this star is located 444 light years away from the Sun. It is moving further from the Earth with a heliocentric radial velocity of +7 km/s.^[2]

22 Tauri

22 Tauri in the Pleiades cluster (circled), with 21 Tauri seen in the upper right
Observation data Epoch J2000      Equinox J2000
Constellation	Taurus
Right ascension	03h 46m 02.90030s[1]
Declination	+24° 31′ 40.4313″[1]
Apparent magnitude (V)	6.43[2]
Characteristics
Spectral type	A0 Vn[3]
B−V color index	−0.020±0.006[2]
Astrometry
Radial velocity (Rv)	+6.9±1.3[2] km/s
Proper motion (μ)	RA: +19.599[1] mas/yr Dec.: −45.077[1] mas/yr
Parallax (π)	7.3453±0.0921 mas[1]
Distance	444 ± 6 ly (136 ± 2 pc)
Absolute magnitude (MV)	1.00[2]
Details
Radius	3.1[4] R☉
Luminosity	63.6[2] L☉
Surface gravity (log g)	4.209±0.113[5] cgs
Temperature	11,817±191[5] K
Metallicity [Fe/H]	−0.1[6] dex
Rotational velocity (v sin i)	232[6] km/s
Other designations
Sterope II[7], 22 Tau, BD+24°556, GC 4506, HD 23441, HIP 17588, HR 1152, SAO 76164[8]
Database references
SIMBAD	data

22 Tauri

This is an ordinary A-type main-sequence star with a stellar classification of A0 Vn.^[3] The 'n' suffix indicates the spectrum displays "nebulous" absorption lines due to rapid rotation. This is confirmed by a high projected rotational velocity of 232 km/s.^[6] The star is radiating sixty times the Sun's luminosity from its photosphere at an effective temperature of 11,817 K.^[5]