Pi Tauri

Pi Tauri (π Tauri) is a solitary,^[9] yellow-hued star in the zodiac constellation of Taurus. With an apparent visual magnitude of +4.69,^[2] it is bright enough to be visible to the naked eye. Although it appears to lie among the stars of the Hyades cluster, it is not itself a member, being three times farther from Earth than the cluster. The distance to this star, as determined using an annual parallax shift of 7.83 mas as seen from the Earth,^[1] is around 420 light years. At that range, the visual magnitude of the star is diminished by an extinction factor of 0.24 due to interstellar dust.^[5]

Pi Tauri

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Taurus
Right ascension	04h 26m 36.37093s[1]
Declination	+14° 42′ 49.6126″[1]
Apparent magnitude (V)	+4.69[2]
Characteristics
Spectral type	G7 IIIa Fe-1[3]
U−B color index	+0.72[2]
B−V color index	+0.98[2]
Astrometry
Radial velocity (Rv)	+31.4±0.3[4] km/s
Proper motion (μ)	RA: −9.52[1] mas/yr Dec.: −31.44[1] mas/yr
Parallax (π)	7.83±0.22 mas[1]
Distance	420 ± 10 ly (128 ± 4 pc)
Absolute magnitude (MV)	−1.27[5]
Details
Mass	3.94[5] M☉
Radius	21[6] R☉
Luminosity	229[7] L☉
Surface gravity (log g)	2.54[5] cgs
Temperature	5,086[7] K
Metallicity [Fe/H]	−0.08[5] dex
Age	17[5] Myr
Other designations
π Tau, 73 Tau, BD+14°697, HD 28100, HIP 20732, HR 1396, SAO 93935[8]
Database references
SIMBAD	data

This is an evolved G-type giant star with a stellar classification of G7 IIIa Fe-1,^[3] where the suffix notation indicates an underabundance of iron in the spectrum. The measured angular diameter is 1.55±0.06 mas.^[10] At the estimated distance of Pi Tauri, this yields a physical size of about 21 times the radius of the Sun.^[6] It possesses nearly four^[5] times the mass of the Sun and is radiating 229 times the Sun's luminosity at an effective temperature of 5,086 K.^[7]