A low-amplitude (less than 0.1 mag.), extrinsic, main-sequence variable with a B0p–B9p spectrum; abbr. SXARI. The spectral lines of He I and Si III are of variable intensity. The variations in brightness, spectrum, and magnetic field are caused by the star’s rotation, with a typical period of about 1 day. Many features resemble those of an Alpha2 Canum Venaticorum star, but the spectrum is earlier and the period generally shorter. SX Arietis itself has an amplitude of 0.06 mag. and a period of 0.73 days.