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Abstract: We present a new method that investigates the evolutionary history of thepulsating DB white dwarf GD358 using asteroseismology. This is done consideringthe internal C-O profile, which describes the relative abundances of carbon andoxygen from the core of the star to its surface. Different evolutionarychannels lead to the generation of different C-O profiles, and these affect thepulsation periods. We used C-O profiles associated with white dwarfs thatevolved through binary evolution channels where the progenitor experienced oneor two episodes of mass loss during one or two common envelope CE phases, andtwo profiles from single star evolution. We computed models using thesedifferent profiles and used a genetic algorithm GA to optimize the search inthe parameter space in order to find the best-fit to the observed pulsationperiods. We used three-parameter models, adjusting the stellar mass, theeffective temperature, and the helium mass of the external layer. Our resultssuggest that binary evolution profiles may provide a better match to thepulsation periods of GD 358. The best-fit to the observations is obtained usinga profile related to an evolutionary history where two episodes of mass losshappen during two CE phases. The best-fit model has a mass close to the meanmass for DB white dwarfs found in various works, and a temperature consistentwith UV spectra obtained with the IUE satellite.



Autor: J. M. Gonzalez Perez, T. S. Metcalfe

Fuente: https://arxiv.org/







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