Summary: A&A manuscript no.
(will be inserted by hand later)
Your thesaurus codes are:
08 (08.01.1; 08.01.3; 08.03.2)
ASTRONOMY
AND
ASTROPHYSICS
23.12.1996
Properties of He­rich stars. I Their evolutionary state and
helium abundance ?; ??
M. Zboril 1??? , P. North 3 , Yu. V. Glagolevskij 2 , and F. Betrix 3
1 Armagh Observatory, Armagh, College Hill, BT61 9DG, Northern Ireland
2 Special Astrophysical Observatory, Nizhnyj Arkhyz, Russia
3 Institute d'Astronomie de l'Universit'e de Lausanne , CH­1290, Chavannes­des­Bois, Switzerland
Received date; accepted date
Abstract. A determination of the surface gravity and an abundance analysis of helium in a sample of 17 He­rich
and 5 normal, reference stars is presented. These results are derived from low resolution CCD spectra, but each star
was measured at least 6 times in order to obtain a significant average spectrum for the spectroscopic variables. The
helium abundances derived from the models used are very close to 0:1 for normal, reference stars and are larger for
the others, clearly indicating the He­rich phenomenon in them. NLTE effects, errors on the microturbulence value or

Source: Armagh Observatory

Collections: Physics