EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 439/3 Article
Free access article

Issue A&A
Volume 439, Number 3, September I 2005
Page(s) L31 - L34
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:200500154



A&A 439, L31-L34 (2005)
DOI: 10.1051/0004-6361:200500154

Letter

Can pulsating PG 1159 stars place constraints on the occurrence of core overshooting?

A. H. Córsico1 and L. G. Althaus1, 2

1  Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque, s/n, 1900 La Plata, Argentina
2  Departament de Física Aplicada, Universitat Politècnica de Catalunya, Av. del Canal Olímpic, s/n, 08860 Castelldefels, Spain
    e-mail: [acorsico;althaus]@fcaglp.unlp.edu.ar

(Received 18 May 2005 / Accepted 8 July 2005)

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 PG 1159 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 PG 1159 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.


Key words: stars: evolution -- stars: interiors -- stars: white dwarfs -- stars: oscillations -- stars: convection

SIMBAD Objects



© ESO 2005


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.