To try to understand the behavior of helium variability in Chemically Peculiar stars, we continued our on-going observational campaign started by Catanzaro, Leone & Catalano (1999). In this paper we present a new set of time resolved spectroscopic observations of the HeI5876 Å line for a sample of 10 stars in the spectral range B3 - A2 and characterized by different overabundances. This line does not show variability in two stars: HD 77350 and HD 175156. It shows instead an equivalent width variation in phase with the Hipparcos light curve for two stars: HD 79158 and HD 196502. Antiphase variations have been found in 4 stars of our sample, namely: HD 35502, HD 124224, HD 129174 and HD 142990. Nothing we can say about HD 115735 because of the constancy of Hipparcos photometric data, while no phase relation has been observed for HD 90044. In the text we discuss the case of HD 175156, according to photometric calibration and our spectroscopic observations we rule out the membership of this star to the main sequence chemically peculiar stars. We confirm the results obtained in the previous paper for which phase relations between light, spectral and magnetic variations are not dependent on stellar spectral type or peculiarity subclass.
|Titolo:||Variability of the HeIλ5876 Å line in early type chemically peculiar stars.|
|Data di pubblicazione:||2003|
|Appare nelle tipologie:||1.1 Articolo in rivista|