1 Arietis

1 Arietis is a double star^[3] in the northern constellation of Aries. 1 Arietis is the Flamsteed designation. The pair have a combined visual magnitude of 5.86,^[2] making it faintly visible to the naked eye. Based upon an annual parallax shift of 5.57 mas,^[1] the distance to the two stars is approximately 590 light-years (180 parsecs). As of 2016, the secondary had an angular separation of 2.90″ along a position angle of 165° from the primary.^[6] They are moving further from the Earth with a heliocentric radial velocity of +7 km/s.^[4]

1 Arietis

Observation data Epoch J2000      Equinox J2000
Constellation	Aries
Right ascension	01h 50m 08.56984s[1]
Declination	+22° 16′ 31.2100″[1]
Apparent magnitude (V)	5.86[2] (6.4/7.2)[3]
Characteristics
Spectral type	K1 III + A6 V[3]
U−B color index	+0.5[2]
B−V color index	+0.74[2]
Astrometry
Radial velocity (Rv)	6.95±0.13[4] km/s
Proper motion (μ)	RA: –16.52[1] mas/yr Dec.: –8.25[1] mas/yr
Parallax (π)	5.57±0.75 mas[1]
Distance	approx. 590 ly (approx. 180 pc)
Absolute magnitude (MV)	−0.39[4]
Details
Luminosity	141.51[4] L☉
Other designations
1 Ari, BD+21°243, HIP 8544, HR 530, SAO 74966, ADS 1457, WDS J01501+2217[5]
1 Ari A: HD 11154.
1 Ari B: HD 11155.
Database references
SIMBAD	data

The brighter star, designated component A, is a magnitude 6.40 giant star with a stellar classification of K1 III. The companion star, component B, is a magnitude 7.20 A-type main sequence star with a classification of A6 V.^[3] Helmut Abt (1985) had this star classified as A3 IV,^[7] matching a more evolved subgiant.