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Characterization of M-dwarf Stars using (N)IR wavelengths

Bárbara Rojas-Ayala

M dwarfs are the most numerous and long-lived stars and therefore can provide valuable information about the Galaxy and star/planet formation. However, their basic properties are tricky to measure using standard techniques for solar stars; they are intrinsically faint at visible wavelengths and their optical spectra exhibit strong molecular absorption.

I will present the metallicity and effective temperature techniques developed for M dwarf stars based on absorption features present in their modest resolution (R ~2700) K-band spectra and other ones based on their colors. These techniques have been calibrated using FGK+M dwarf pairs and synthetic atmosphere models. I will compare their results with other empirical measurements of low mass stars in the literature, and I will discuss the usefulness of the K-band methods for the characterization of exoplanet systems. Finally, I will show a new photometric technique based on IR/Optical magnitudes that provides [Fe/H] estimates accurate to RMSE ~0.12 dex for thousands of early M dwarfs in the SUPERBLINK survey.

2013 October 31, 13:30

Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto

Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia