| Issue |
A&A
Volume 473, Number 2, October II 2007
|
|
|---|---|---|
| Page(s) | 579 - 587 | |
| Section | Stellar atmospheres | |
| DOI | https://doi.org/10.1051/0004-6361:20077539 | |
| Published online | 23 July 2007 | |
New homogeneous iron abundances of double-mode Cepheids from high-resolution echelle spectroscopy*
1
Department of Optics & Quantum Electronics, University of Szeged, POB 406, Szeged 6701, Hungary e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
2
INAF - Osservatorio Astronomico di Brera, via Bianchi 46, 23807 Merate, Italy
3
Konkoly Observatory of the Hungarian Academy of Sciences, POB 67, Budapest 1525, Hungary
Received:
26
March
2007
Accepted:
18
June
2007
Abstract
Aims.We define the relationship between the double-mode pulsation of Cepheids and metallicity in a more accurate way, determine the empirical metallicities of double-mode Cepheids from homogeneous, high-resolution spectroscopic data, and study of the period-ratio – metallicity dependence.
Methods. The high S/N echelle spectra obtained with the FEROS spectrograph were analyzed using a self-developed IRAF script, and the iron abundances were determined by comparing with synthetic spectra assuming LTE.
Results.Accurate [Fe/H] values of 17 galactic beat Cepheids were determined. All these stars have solar or slightly subsolar metallicity. Their period ratio (
) shows strong correlation with their derived [Fe/H] values. The corresponding period ratio – metallicity relation has been evaluated.
Key words: stars: variables: Cepheids / stars: atmospheres / stars: general
Based on observations taken with the ESO 2.2-m telescope at La Silla, Chile (Proposal 073.D-0072) and the 1.82 m telescope at David Dunlap Observatory, Canada.
© ESO, 2007
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