Spectrophotometric studies of Ap stars

Abstract

Based on the observed energy distribution curves of about a hundred Ap stars, the various relationships among their physical parameters: namely, the temperatue, colour index, bolometric correction and bolometric magnitude have been studied. The hotter Ap stars have been found to be apparently bluer than their normal counterparts, which is possible due to the broad continuum features at λ4200 and λ5200 that are generally present in Ap stars only. The bolometric corrections are independent of parallax measurements; the Ap stars as well as the normal stars follow the same sequence of bolometric corrections when related to temperature. The Ap stars appear to be slightly evolved and their position in the HR diagram indicates the hydrogen shell burning phase. The mass range of Ap stars is similar to that of normal A stars.