Dust shells around high-latitude A-type stars

Abstract
Near-infrared (JHKL) photometry is presented for three A-type stars, HD 231, HD 3003 and HD 213985. Although all three appear to have cool dust shells, only in HD 213985 is the dust sufficiently warm to produce a near-infrared excess. HD 213985 shows remarkably regular variability with a period of 254 d and an amplitude, ΔK = 0.29 mag. No entirely satisfactory explanation for this variability is offered, though various possibilities are discussed. Radial pulsations are shown to be inconsistent with the available information and non-radial pulsations seem highly unlikely. The star may be a binary system, but in this case the character of the infrared variation in particular would seem to imply a rather contrived geometry for the system.

This publication has 0 references indexed in Scilit: