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Projeto Observacional para 2017B - OP2017B-003

Autor: Riano Escate Giribaldi
Instituição: UFRJ

Gustavo F. Porto de Mello
Diego Lorenzo Oliveira

Título: Accurate Halpha Balmer profile diagnostics

Resumo: Constraining realistic physical properties of stars such as mass, radius and luminosity depends of how accurate the effective temperature Teff is measured. It is a topic of great interest since the discovery of exoplanets, whose characterization depends on the accurate knowledge of the host stars. The Halpha fitting is preffered to derive Teff in star clusters due to its little dependence on other parameters and its full independence of reddening. The Balmer lines theory of [1] was tested on the Sun by [2,3,4] who find a Teff 35 K cooler than 5777 K, and by [5] who find 100 K cooler. These results promoted a new revision of the theory by [6] which produced temperatures 100 K cooler. Using long-slit spectra obtained at OPD we found that Teff(Halpha) agree with the photometric Teffs of [7] and Teff underestimations may be due to normalization of echelle spectra. We propose to observe a sample of FGK stars to extend results.