Issue |
A&A
Volume 638, June 2020
|
|
---|---|---|
Article Number | A30 | |
Number of page(s) | 7 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/202037743 | |
Published online | 05 June 2020 |
On the formation of hydrogen-deficient low-mass white dwarfs
1
Instituto de Astrofísica de La Plata, CONICET–UNLP, La Plata, Argentina
2
Facultad de Ciencias Astronómicas y Geofísicas, UNLP, La Plata, Argentina
e-mail: tbattich@fcaglp.unlp.edu.ar
Received:
14
February
2020
Accepted:
28
March
2020
Context. Two of the possible channels for the formation of low-mass (M⋆ ≲ 0.5 M⊙) hydrogen-deficient white dwarfs are the occurrence of a very-late thermal pulse after the asymptotic giant-branch phase or a late helium-flash onset in an almost stripped core of a red giant star.
Aims. We aim to asses the potential of asteroseismology to distinguish between the hot flasher and the very-late thermal pulse scenarios for the formation of low-mass hydrogen-deficient white dwarfs.
Methods. We computed the evolution of low-mass hydrogen-deficient white dwarfs from the zero-age main sequence in the context of the two evolutionary scenarios. We explore the pulsation properties of the resulting models for effective temperatures characterizing the instability strip of pulsating helium-rich white dwarfs.
Results. We find that there are significant differences in the periods and in the period spacings associated with low radial-order (k ≲ 10) gravity modes for white-dwarf models evolving within the instability strip of the hydrogen-deficient white dwarfs.
Conclusions. The measurement of the period spacings for pulsation modes with periods shorter than ∼500 s may be used to distinguish between the two scenarios. Moreover, period-to-period asteroseismic fits of low-mass pulsating hydrogen-deficient white dwarfs can help to determine their evolutionary history.
Key words: white dwarfs / asteroseismology / stars: evolution / stars: interiors / stars: oscillations / stars: low-mass
© ESO 2020
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