Delta2 Tauri

Delta² Tauri (δ² Tauri) is a solitary,^[10] white-hued star in the zodiac constellation of Taurus. Based upon an annual parallax shift of 20.21 mas as seen from Earth,^[1] it is located roughly 161 light years distant from the Sun. It is separated from δ¹ Tauri by 0.3° on the sky^[11] and is faintly visible to the naked eye with an apparent visual magnitude of +4.80.^[2] The star is considered a member of the Hyades cluster.^[12]

For other stars with this Bayer designation, see δ Tauri.

Delta² Tauri

Location of δ2 Tauri in the Hyades, indicated by its Flamsteed designation 64
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Taurus
Right ascension	04h 24m 05.75985s[1]
Declination	+17° 26′ 38.8583″[1]
Apparent magnitude (V)	+4.80[2]
Characteristics
Evolutionary stage	main sequence
Spectral type	A2 Vs[3]
U−B color index	+0.12[2]
B−V color index	+0.15[2]
Astrometry
Radial velocity (Rv)	+37.1[4] km/s
Proper motion (μ)	RA: +108.16[1] mas/yr Dec.: −34.66[1] mas/yr
Parallax (π)	20.21±0.40 mas[1]
Distance	161 ± 3 ly (49.5 ± 1.0 pc)
Absolute magnitude (MV)	+1.62[5]
Details
Mass	1.79[6] M☉
Radius	1.8[7] R☉
Luminosity	27[8] L☉
Surface gravity (log g)	4.15[4] cgs
Temperature	7,997[4] K
Metallicity [Fe/H]	+0.14[4] dex
Rotational velocity (v sin i)	42[4] km/s
Age	449[6] Myr
Other designations
δ2 Tau, 64 Tauri, BD+17°714, HD 27819, HIP 20542, HR 1380, SAO 93907[9]
Database references
SIMBAD	data

At the estimated age of 449 million years,^[6] this is an A-type main-sequence star with a stellar classification of A2 Vs,^[3] where the 's' suffix indicates narrow (sharp) absorption lines. It has 1.8^[6] times the mass of the Sun and about 1.8^[7] times the Sun's radius. The star is radiating 27^[8] times the Sun's luminosity from its photosphere at an effective temperature of 7,997 K.^[4]

δ² Tauri is a source of X-ray emission with a luminosity of 101.1×10²⁰ W. Since A-type stars are not normally a source of X-rays, this emission may be coming from an unknown companion or from a line of sight source.^[13]