A Search for Temporal Variations of Interstellar Ca II

Open Access

1 October 1976

journal article
Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society

Vol. 177 (1) , 79-89
https://doi.org/10.1093/mnras/177.1.79

Abstract

Using high dispersion Coudé observations a search has been made for changes with time of the interstellar Ca II K line. The star HD 25558 has been investigated in detail. Some other stars in which discrepant measures had previously been reported have been re-examined. It is found that relatively strong ( ⩾ 100 mÅ) stellar absorption in the K line is responsible for the differences. There is no evidence for time variations in the interstellar K line. It is shown how stellar K can be a major source of error in the measurement of interstellar K, especially for B-type stars which exhibit low rotational velocities (Vsini < 100 km s^–1). Other candidates for temporal variations of interstellar K are discussed.

Keywords

This publication has 0 references indexed in Scilit: