IUE observations of the broad continuum feature at 1400 A in the silicon and related stars.

Abstract

The upper main sequence chemically peculiar stars have previously been studied spectrophotometrically using low resolution TD-1 spectra. These show that the broad continuum feature at 1400 Å is a useful indicator of Si anomaly. In this paper the authors extend this to IUE low resolution spectra and show that this feature is indeed well correlated with Si and also with optical chemical peculiarity indices. The authors further demonstrate its utility in selecting silicon stars. This feature is likely due to autoionization of Si II and is the best available discriminator of the overabundance of a key element in the Ap stars.