Presentation #109.01D in the session Cataclysmic Variables, Novae, Symbiotic Stars and White Dwarfs.
Pulsating White Dwarf stars tell us about their internal chemical makeup. Stellar interiors encapsulate their evolution history, and can reveal insights to their evolutionary pasts. In this talk, I will discuss two examples of how changing the structure of a white dwarfs from prior evolutionary processes impacts their ensuing pulsation properties.
First, I will discuss how white dwarf seismology can detect the presence/absence of 22Ne. The amount of 22Ne in a white dwarf is tied to its birth metallicity. Neglecting 22Ne in white dwarf models may be ignoring the impact of the stars’ initial metallicity.
Second, I will discuss how certain trapped modes may constrain the 12C(α,γ)16O reaction rate. This reaction occurs during core helium burning in stellar evolution, and is of fundamental importance in nuclear astrophysics; the rate of this reaction determines the C/O ratio of our universe. We find certain signature g-mode periods to distinguish the 12C(α,γ)16O reaction rate probability distribution function, even under the inclusion of overshooting in the stars’ evolution history. Thus, white dwarf seismology may further constrain the 12C(α,γ)16O reaction rate, and overall be a promising avenue to reveal details of stellar interiors and their evolutionary pasts.