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Projeto Observacional para 2016A - SO2016A-005

Autor: Ingrid Pelisoli
Instituição: Outros
e-mail: ingrid.pelisoli@gmail.com

Kepler de Souza Oliveira

Título: Time Resolved Spectroscopy of the Lowest Mass White Dwarfs

Resumo: Extremely-low mass white dwarfs were first found as companions to pulsars, followed by companions to other white dwarfs and main sequence stars (The ELM Survey: Brown et al. 2010, Kilic et al. 2011, Brown et al 2011, Kilic et al. 2012, Brown et al. 2013, Gianninas et al. 2015) and finally as pulsators (Hermes et al. 2012, 2013a, 2013b). For the SDSS DR12 catalog, we found a few thousand stars with log g around 5.5, five external sigma from the upper limit of the main sequence, even for extremely-low metallicity. The multi-exposures of the SDSS are not sufficient to study their radial velocity variability to determine if they are members of binary systems and therefore clear extremely-low mass white dwarfs, which can only be formed in such systems in the age of the Universe.