Determinação de parâmetros atmosféricos de estrelas em NGC 6528 e NGC 6553 - aglomerados globulares de referência para o estudo de populações ricas em metais / Derivation of atmospheric parameters of stars in NGC 6528 and NGC 6553 - globular clusters of reference for the study of metal-rich populations

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

The metal-rich bulge globular clusters are a keystone for the understanding of the evolutionary history of our Galaxy and the study of the bulge stellar populations provides constraints to models of bulge formation. In this work we present the study of 22 stars in the globular clusters NGC 6528 and NGC 6553, templates of the metal-rich populations of the bulge. With the use of photometric and spectroscopic data, we have found the radial velocities, effective temperatures, gravities and metallicities of these stars. The parameters found are in the range 3200 <= Tef <= 5000K and -0.5 <= log g <= 2.4, covering from the Horizontal Branch to the tip of the Red Giant Branch evolutionary stages. The mean metallicity determined was [Fe/H] = -0.5 dex, from the Lick indices, calibrations of equivalent widths of TiO as a function of stellar parameters and comparisons to the synthetic spectra. A trend is found for an overabundance of a elements. These stars are templates for the study of old metal-rich stellar populations and the fitting of the synthetic spectra to the observed stellar spectra is an important check of the quality of the synthetic spectra for stellar population synthesis.

ASSUNTO(S)

astrophysics estelar parÂmetros atmosfÉricos astronomia astronomy atmospheric parameters astrofÍsica estelar

Documentos Relacionados