15 Arietis (abbreviated 15 Ari) is a single^[8] 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,^[8] 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^[5] in magnitude because of extinction from interstellar gas and dust.

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.^[9] At the estimated distance of Delta Ophiuchi,^[2] this yields a physical size of about 67 times the radius of the Sun.^[10] The radius determined from the observed brightness and colour of the star is 87 R_☉.^[6]

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]