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arXiv · 1809.09242

Evolution and Asteroseismology of Pulsating Low-Mass White Dwarfs

L. M. Calcaferro·A. H. Córsico·L. G. Althaus·A. D. Romero·S. O. Kepler
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Abstract

Many low-mass white dwarfs are being discovered in the field of our galaxy and some of them exhibit $g$-mode pulsations, comprising the extremely low-mass variable (ELMV) stars class. Despite it is generally believed that these stars are characterized by thick H envelopes, from stellar evolution considerations, the existence of low-mass WDs with thin H envelopes is also possible. We have performed detailed asteroseismological fits to all the known ELMVs to search for a representative model by employing a set of fully evolutionary models that are representative of low-mass He-core white dwarf stars with a range of stellar masses $[0.1554-0.4352]\ M_{\odot}$, effective temperatures $[6000-10000]\ $K, and also with a range of H envelope thicknesses $-5.8 \lesssim \log(M_{\rm H}/M_{\star}) \lesssim -1.7$, hence expanding the space of parameters. We found that some of the stars under analysis are characterized by thick H envelopes, but others are better represented by models with thin H envelope.

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L. M. Calcaferro, A. H. Córsico, L. G. Althaus, A. D. Romero, S. O. Kepler. 2018-09-24. Evolution and Asteroseismology of Pulsating Low-Mass White Dwarfs. https://arxiv.org/abs/1809.09242

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