SpringerLink
Forum Springer Astron. Astrophys.
Forum Whats New Search Orders


Astron. Astrophys. 320, 257-264 (1997)

Next Section Table of Contents

The importance of a correct abundance assumption in determining the effective temperature and gravity of stars

A spectroscopic study of the helium weak stars HD 5737, HD 175362 and HD 202671 *

F. Leone 1 and M. Manfrè 2

1 Osservatorio Astrofisico di Catania, Città Universitaria, I-95125 Catania, Italy
2 Istituto di Astronomia, Università di Catania, Città Universitaria, I-95125 Catania, Italy

Received 3 May 1996 / Accepted 17 September 1996

Abstract

Even if metal and helium abundances characterize the stellar atmosphere structure, the effective temperature and gravity of stars are generally determined assuming the solar chemical composition. To investigate the importance of such a simplification, we have performed high resolution spectroscopy of the [FORMULA] region for the helium weak stars HD 5737, HD 175362 and HD 202671, which are also known to be metal rich. By spectral synthesis of the [FORMULA] line profile, the effective temperature and gravity of these stars have been inferred using atmosphere models whose metal opacity scale, metal and helium abundances were consistent with the derived abundances. It appears that the effective temperature and gravity are under-estimated if the metal and/or the helium abundance are under-estimated. For HD 175362 the richest in metal star of our sample, without taking into account the correct metal and helium abundance the effective temperature can be under-estimated up to 7% and the logarithm of gravity can be under-estimated up to 0.25 dex.

Key words: line: identification – stars: abundances – stars: chemically peculiar – stars: individual: HD 5737, HD 175362 and HD 202671

* Based on observations collected at the European Southern Observatory, LaSilla Chile.

Send offprint requests to: F. Leone

SIMBAD Objects

Contents

Next Section Table of Contents

© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998
helpdesk.link@springer.de