Volume 372, Number 2, June III 2001
|Page(s)||544 - 550|
|Section||Interstellar and circumstellar matter|
|Published online||15 June 2001|
Pulsational constraints to the metallicity gradient in the Galactic disk
Osservatorio Astronomico di Roma, Via di Frascati 33, 00040 Monteporzio Catone, Italy
2 Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
3 Observatoire de Genève, Switzerland e-mail: email@example.com; firstname.lastname@example.org; email@example.com;
Corresponding author: M. Marconi, firstname.lastname@example.org
Accepted: 26 March 2001
BVI data of Galactic Cepheids observed in the solar neighborhood and in the outer disk are analyzed on the basis of nonlinear, non-local and time-dependent convective pulsating models computed for different assumptions on the chemical composition. We show that the theoretical color-color, period-luminosity, and period-luminosity-color relations, as predicted by the models with varying metal content, provide the way to simultaneously estimate the true distance modulus and the metal content Z of each individual variable. On this basis, we estimate that the metallicity distribution of Cepheids with Galactocentric distances d from ~6 to ~19 kpc can be represented by a linear gradient of dex kpc-1, which is close to previous empirical determinations based on Cepheids, Planetary Nebulae and HII regions. However, our results are not excluding a different scenario, such as a two-zone model with a discontinuity in metallicity near kpc (see Twarog et al. 1997).
Key words: stars: variables: Cepheids / stars: oscillations / stars: distances
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.