English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We reexamine the theoretical instability domain of pulsating PG1159 stars (GWVir variables). We performed an extensive g-mode stability analysis on PG1159evolutionary models with stellar masses ranging from 0.530 to 0.741 Mo forwhich the complete evolutionary stages of their progenitors from the ZAMS,through the thermally pulsing AGB and born-again phases to the domain of thePG1159 stars have been considered. We found that pulsations in PG1159 stars areexcited by the kappa-mechanism due to partial ionization of carbon and oxygen,and that no composition gradients are needed between the surface layers and thedriving region, much in agreement with previous studies. We show, for the firsttime, the existence of a red edge of the instability strip at highluminosities. We found that all of the GW Vir stars lay within our theoreticalinstability strip. Our results suggest a qualitative good agreement between theobserved and the predicted ranges of unstable periods of individual stars.Finally, we found that generally the seismic masses (derived from the periodspacing) of GW Vir stars are somewhat different from the masses suggested byevolutionary tracks coupled with spectroscopy. Improvements in the evolutionduring the thermally pulsing AGB phase and/or during the core helium burningstage and early AGB could help to alleviate the persisting discrepancies.Comment: 10 pages, 8 figures. To be published in Astronomy and Astrophysic

New nonadiabatic pulsation computations on full PG 1159 evolutionary models: the theoretical GW Virginis instability strip revisited