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تسجيل مستخدم جديدOn the formation of hydrogen-deficient low-mass white dwarfs
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Two of the possibilities for the formation of low-mass ($M_{star}lesssim 0.5,M_{odot}$) 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. 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. We compute 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. We find that there are significant differences in the periods and in the period spacings associated with low radial-order ($klesssim 10$) gravity modes for white-dwarf models evolving within the instability strip of the hydrogen-deficient white dwarfs. The measurement of the period spacings for pulsation modes with periods shorter than $sim500,$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.
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