37 Tauri

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

37 Tauri is a single,^[9] orange-hued star in the zodiac constellation of Taurus. It can be seen with the naked eye, having an apparent visual magnitude of 4.36.^[2] A magnitude 10.01 visual companion has an angular separation of 134.30″ on a position angle of 138.6°, as of 2003.^[10] Based on an annual parallax shift of 17.43±0.21 mas,^[1] 37 Tauri is about 187 light years away. It is moving further from the Sun with a heliocentric radial velocity of 9.5 km/s.^[6]

37 Tauri

Observation data Epoch J2000      Equinox J2000
Constellation	Taurus
Right ascension	04h 04m 41.71484s[1]
Declination	+22° 04′ 54.9243″[1]
Apparent magnitude (V)	4.36[2]
Characteristics
Spectral type	K0 III-IIIb[3]
U−B color index	0.95[4]
B−V color index	1.07[5]
R−I color index	0.53[4]
Astrometry
Radial velocity (Rv)	+9.52±0.11[6] km/s
Proper motion (μ)	RA: +90.53[1] mas/yr Dec.: −59.47[1] mas/yr
Parallax (π)	17.43±0.21 mas[1]
Distance	187 ± 2 ly (57.4 ± 0.7 pc)
Absolute magnitude (MV)	0.57[2]
Details
Mass	1.99[5] M☉
Radius	10.15±0.69[7] R☉
Luminosity	60±6[7] L☉
Surface gravity (log g)	2.77[7] cgs
Temperature	4,732±26[5] K
Metallicity [Fe/H]	+0.01[7] dex
Rotational velocity (v sin i)	2.8[6] km/s
Age	1.39[5] Gyr
Other designations
37 Tau, BD+21°585, FK5 1112, HD 25604, HIP 19038, HR 1256, SAO 76430, WDS J04047+2205A[8]
Database references
SIMBAD	data

This is an evolved K-type giant star with a stellar classification of K0 III-IIIb.^[3] At the age of 1.39^[5] billion years, it has become a red clump giant, indicating that it is generating energy through helium fusion at its core.^[11] The star has around double the mass of the Sun and has expanded to 10^[7] times the Sun's radius. It is radiating roughly 60^[7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,732 K.^[5]

Chinese astronomy

In Chinese astronomy, 37 Tauri is called 月, Pinyin: Yuè, meaning Moon, because this star is marking itself and stand alone in Moon asterism, Hairy Head mansion (see : Chinese constellation).^[12]