15 Arietis

15 Arietis (abbreviated 15 Ari) is a single^[9] variable star in the northern constellation of Aries. 15 Arietis is the Flamsteed designation; it also bears the variable star designation AV Arietis. It has an apparent visual magnitude of 5.74,^[9] which is just bright enough to be visible to the naked eye from dark suburban skies. An annual parallax shift of 5.84 mas^[2] corresponds to a physical distance of approximately 560 light-years (170 parsecs) from Earth. At that distance, the star's brightness is reduced by 0.33^[6] in magnitude because of extinction from interstellar gas and dust.

15 Arietis

A visual band light curve for 15 Arietis, plotted from data presented by Tabur et al. (2009)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Aries
Right ascension	02h 10m 37.59642s[2]
Declination	+19° 30′ 01.2099″[2]
Apparent magnitude (V)	5.67 - 5.74[3]
Characteristics
Evolutionary stage	AGB[4]
Spectral type	M3 III[1]
U−B color index	+1.91[5]
B−V color index	+1.64[5]
Variable type	SRs[3]
Astrometry
Radial velocity (Rv)	+62.04 ± 0.22[6] km/s
Proper motion (μ)	RA: +87.88[2] mas/yr Dec.: -27.82[2] mas/yr
Parallax (π)	5.84±0.49 mas[2]
Distance	560 ± 50 ly (170 ± 10 pc)
Absolute magnitude (MV)	−0.9[7]
Details
Mass	1.4[7] M☉
Radius	87[7] R☉
Luminosity	781[8] L☉
Temperature	3,565[8] K
Other designations
AV Arietis, BD+18°277, FK5 1056, HD 13325, HIP 10155, HR 631, SAO 92822
Database references
SIMBAD	data

This is a red giant star with a stellar classification of M3 III.^[1] The measured angular diameter of this star is 3.67 ± 0.11 mas.^[10] At its estimated distance,^[2] this yields a physical size of about 67 times the radius of the Sun.^[11] The radius determined from the observed brightness and colour of the star is 87 R_☉.^[7]

15 Arietis is a short period semiregular variable with the designation AV Arietis. The period given in the General Catalogue of Variable Stars is 5.032 days.^[3] Longterm photometry finds that the strongest pulsation period is 18.1 days with an amplitude of 0.028 magnitudes, while a second is 21.9 days and 0.030 in magnitude.^[1]