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Projeto Observacional para 2017A - OP2017A-010

Autor: Riano Escate Giribaldi
Instituição: UFRJ

Gustavo F. Porto de Mello

Título: Accurate Halpha Balmer profile diagnostics and correction for echelle spectra

Resumo: Constraining realistic physical properties of stars such as mass, radius and luminosity depends of how accurate the effective temperature Teff is measured. This became a topic of great interest with the discovery of exoplanets whose characterization depends on the accurate knowledge of the host stars. Among the methods to derive Teff, in star clusters, the Halpha profile fitting is preferred due to its low dependence on other parameters and its full independence of reddening. The Balmer lines theory (Barklem+2000) was tested on echelle spectra and seemed to produce temperatures ~30 K cooler than interferometric values, which caused a new revision by Allard+2008 which produced temperatures even cooler ~100 K. Using long-slit spectra (R=43000 & S/R>250) obtained at OPD we found that systematics related to normalization of echelle spectra produce Teff underestimations of ~25K. We porpose time to observe an extended sample of FGK stars.