Astronomy and Astrophysics – Astronomy
Scientific paper
Jul 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004apj...610..436q&link_type=abstract
The Astrophysical Journal, Volume 610, Issue 1, pp. 436-442.
Astronomy and Astrophysics
Astronomy
37
Stars: Abundances, Stars: Agb And Post-Agb, Stars: Interiors, Stars: Oscillations, Stars: White Dwarfs
Scientific paper
We revisit the controversial question of the excitation of pulsation modes in models of PG 1159 stars that feature homogeneous envelopes with compositions comparable to those observed at the surface. We find, in agreement with some authors but contrary to others, that g-mode pulsations are naturally excited in such models and that there is no need to invoke composition gradients between the photosphere and the driving region in PG 1159 pulsators. We further find an excellent qualitative agreement between the range of predicted periods and the range of observed periods for all objects in our sample of pulsating stars, except for two models corresponding to the stars with the lowest surface gravities (central stars of planetary nebulae). We also address the problem of the coexistence of both variable and nonvariable PG 1159 stars in the same region of the logg-Teff diagram. We find a natural explanation for this cohabitation in terms of a dispersion in atmospheric parameters and in terms of a variation in surface composition from star to star. In particular, the most He-rich stars tend to be stable. We finally address the puzzling question of the existence of a correlation between pulsations and the presence of traces of nitrogen in the atmospheres of pulsating PG 1159 stars, a challenge that has remained unanswered so far.
Brassard Pierre
Fontaine Gérard
Quirion Pierre-Olivier
No associations
LandOfFree
On the Driving Mechanism and the Coexistence of Variable and Nonvariable Stars in the Domain of the Pulsating PG 1159 Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with On the Driving Mechanism and the Coexistence of Variable and Nonvariable Stars in the Domain of the Pulsating PG 1159 Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Driving Mechanism and the Coexistence of Variable and Nonvariable Stars in the Domain of the Pulsating PG 1159 Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1076062