Magnetospheres and winds in the helium weak stars: Observations of C 5 in upper main sequence CP stars

摘要

A sample is presented of eleven helium weak and Si stars, observed at high dispersion. These are HD 7537, 21699, 28843, 34452, 125823, 131120, 142301, 142990, 144334, 175362 AND 215441. The stars span the range B2.5 to B6 and include both magnetic and nonmagnetic as well as rapid and slow rotators. In the two stars designated sn by Abt, the C IV profile is strong (HD 5737 and 21699) while all of the other stars can be explained by numerous blended lines of Fe III and similar ions. Most of the stars were observed several times, and only HD 21699 appears to show large amplitude spectral variations.