Zeta Arietis

Zeta Arietis is a star in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from ζ Arietis, and abbreviated Zeta Ari or ζ Ari. This star is dimly visible to the naked eye with an apparent visual magnitude of +4.87.^[3] Based upon an annual parallax shift of 12.77 mas,^[2] the distance to this star is approximately 255 light-years (78 parsecs). It is receding from the Sun with a radial velocity of +7 km/s.^[6]

ζ Arietis

Location of ζ Arietis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Aries[1]
Right ascension	03h 14m 54.098s[2]
Declination	+21° 02′ 40.01″[2]
Apparent magnitude (V)	+4.874±0.023[3]
Characteristics
Spectral type	A1 V[4]
U−B color index	−0.01[5]
B−V color index	−0.02[5]
Astrometry
Radial velocity (Rv)	+7.3±2.8[6] km/s
Proper motion (μ)	RA: −26.276 mas/yr[2] Dec.: −72.900 mas/yr[2]
Parallax (π)	12.7708±0.3734 mas[2]
Distance	255 ± 7 ly (78 ± 2 pc)
Absolute magnitude (MV)	+0.35[1]
Details
Mass	2.430±0.340[3] M☉
Radius	2.974±0.115[3] R☉
Luminosity	65.7±4.8[3] L☉
Surface gravity (log g)	3.88±0.07[3] cgs
Temperature	9,528±117[3] K
Rotational velocity (v sin i)	133[7] km/s
Age	333[8] Myr
Other designations
ζ Ari, 58 Arietis, BD+20 527, FK5 1089, GC 3872, HD 20150, HIP 15110, HR 972, SAO 75810, PPM 92319[9]
Database references
SIMBAD	data

This is an A-type main sequence star with a stellar classification of A1 V.^[4] It is an estimated 333^[8] million years old and is spinning rapidly with a projected rotational velocity of 133 km/s.^[7] Zeta Arietis has 2.4 times the mass of the Sun and 3.0 times the Sun's radius.^[3] It is radiating 66 times the luminosity of the Sun from its photosphere at an effective temperature of 9,528 K,^[3] giving it the characteristic white-hued glow of an A-type star.^[10]

Name

This star, along with δ Ari, ε Ari, π Ari, and ρ³ Ari, were Al Bīrūnī's Al Buṭain (ألبطين), the dual of Al Baṭn, the Belly.^[11] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Buṭain was the title for five stars: δ Ari as Botein, π Ari as Al Buṭain I, ρ³ Ari as Al Buṭain II, ε Ari as Al Buṭain III, and ζ Ari as Al Buṭain IV.^[12]

In Chinese, 天陰 (Tiān Yīn), meaning Yin Force, refers to an asterism consisting of ζ Arietis, 63 Arietis, δ Arietis, τ Arietis and 65 Arietis.^[13] Consequently, the Chinese name for ζ Arietis itself is 天陰二 (Lóu Su èr, English: the Second Star of Yin Force.)^[14]