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Title: Seismic Signatures of the 12 C(α, γ) 16 O Reaction Rate in White Dwarf Models with Overshooting
Abstract We consider the combined effects that overshooting and the12C(α,γ)16O reaction rate have on variable white dwarf (WD) stellar models. We find that carbon–oxygen (CO) WD models continue to yield pulsation signatures of the current experimental12C(α,γ)16O reaction rate probability distribution function when overshooting is included in the evolution. These signatures hold because the resonating mantle region, encompassing ≃0.2M⊙in a typical ≃0.6M⊙WD model, still undergoes radiative helium burning during the evolution to a WD. Our specific models show two potential low-order adiabatic g-modes,g2andg6, that signalize the12C(α,γ)16O reaction rate probability distribution function. Both g-mode signatures induce average relative period shifts of ΔP/P= 0.44% and ΔP/P= 1.33% forg2andg6, respectively. We find thatg6is a trapped mode, and theg2period signature is inversely proportional to the12C(α,γ)16O reaction rate. Theg6period signature generally separates the slower and faster reaction rates, and has a maximum relative period shift of ΔP/P= 3.45%. We conclude that low-order g-mode periods from CO WDs may still serve as viable probes for the12C(α,γ)16O reaction rate probability distribution function when overshooting is included in the evolution.  more » « less
Award ID(s):
1927130
PAR ID:
10543931
Author(s) / Creator(s):
; ;
Publisher / Repository:
IOP
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
954
Issue:
1
ISSN:
0004-637X
Page Range / eLocation ID:
51
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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