Evidence of thin helium envelopes in PG1159 stars

Abstract

We present evidence that PG1159 stars could harbour He--rich envelopes substantially thinner than those predicted by current evolutionary models with current estimates of mass loss, which may be attributable to an extensive mass--loss episode during the born--again AGB phase. Specifically, we show that the models with thin He--rich envelopes predict remarkably large magnitudes of the rates of period change of the trapped and untrapped modes observed in the pulsating star PG 1159$-$035. This is a consequence of the much shorter evolutionary timescale of the models with thin He--rich envelopes during the low--gravity PG1159 regime. Our findings are particularly interesting in view of the suggestion of an evolutionary link between the helium--deficient PG1159 star H1504+65 and the recently discovered white dwarfs with almost pure carbon atmospheres.

arXiv comment4 pages, 2 figures. To be published as a Letter in ApJ

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Cited by in corpus (15)

• Evolutionary and pulsational properties of white dwarf stars
• Pulsating White Dwarf Stars and Precision Asteroseismology
• New evolutionary sequences for hot H-deficient white dwarfs on the basis of a full account of progenitor evolution
• The white dwarf luminosity function
• The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035
• Asteroseismology of hot pre-white dwarf stars: the case of the DOV stars PG 2131+066 and PG 1707+427, and the PNNV star NGC 1501
• A 3D Photoionization Model of the Extreme Planetary Nebula NGC 6302
• On the formation of hot DQ white dwarfs
• On the possible existence of short-period g-mode instabilities powered by nuclear burning shells in post-AGB H-deficient (PG1159-type) stars
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: IV. The secular rate of period change
• A Herschel study of NGC 650
• Kepler and TESS Observations of PG 1159-035
• On the origin of white dwarfs with carbon-dominated atmospheres: the case of H1504+65
• A primer on the formation and evolution of hydrogen deficient Central Stars of Planetary Nebulæ and Related Objects
• Analysis of luminosity measurements of the pre-white dwarf PG 1159-035