Interstellar C IV and Si IV in the Direction of Loop I

Abstract

AbstractNearby late-B and early-A stars show clear IS absorptions in Mg II, C II and other lines (IUE spectra). Some of them, in the Sco Cen direction, also show absorption features at C IV and Si IV line wavelengths. We discuss the possible formation of these lines in an intermediate temperature gas region between the dense and cold H I wall and the hot ISM, a region that could be the collision interaction between the Local Bubble and the Loop I supershell. Some individual stellar spectra are presented and discussed.