Can pulsating PG1159 stars place constraints on the occurrence of core overshooting?

Abstract

The present letter is aimed at exploring the influence of overshooting during the central helium burning in pre-white dwarf progenitors on the pulsational properties of PG1159 stars. To this end we follow the complete evolution an intermediate-mass white dwarf progenitor from the zero age main sequence through the thermally pulsing and born-again phases to the domain of the PG1159 stars. Our results suggest that the presence of mode-trapping features in the period spacings of these hot pulsating stars could result from structure in the carbon-oxygen core. We find in particular that in order to get enough core structure consistent with observational demands, the occurrence of overshoot episodes during the central helium burning is needed. This conclusion is valid for thick helium envelopes like those predicted by our detailed evolutionary calculations. If the envelope thickness were substantially smaller, then the occurrence of core overshooting would be more difficult to disentangle from the effects related to the envelope transition zones.

4 pages, including 3 postscript figures. Accepted for publication in Astronomy and Astrophysics Letters

References in corpus (3)

• The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection
• The chemical composition of White Dwarfs as a test of convective efficiency during core He-burning
• White Dwarf Asteroseismology and the ^12C(alpha,gamma)^16O Rate

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• The potential of asteroseismology for probing the core chemical stratification in white dwarf stars
• Asteroseismological constraints on the pulsating planetary nebula nucleus (PG1159-type) RX J2117.1+3412
• Asteroseismological constraints on the coolest GW Vir variable star (PG 1159-type)PG 0122+200
• Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS: I. Asteroseismology of the GW Vir stars RX J2117+3412, HS 2324+3944, NGC 6905, NGC 1501, NGC 2371, and K 1-16
• On the systematics of asteroseismological mass determinations of PG1159 stars
• New DA white dwarf models for asteroseismology of ZZ Ceti stars
• Kepler and TESS Observations of PG 1159-035
• A primer on the formation and evolution of hydrogen deficient Central Stars of Planetary Nebulæ and Related Objects