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arXiv · 2408.15291

A temperature scale of $1\sim2$ eV in the mass-radius relationship of white dwarfs of type DA

Jin Lim·Ji-Yu Kim·Maurice H. P. M. van Putten
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Abstract

The mass-radius relationship of white dwarfs (WDs) is one of their defining characteristics, largely derived from electron degeneracy pressure. We present a model-independent study of the observed mass-radius relationship in WD binaries of \cite{Parsons_2017}, listing data over a broad temperature range up to about 60,000 K (5 eV). The data show an appreciable temperature sensitivity with pronounced intrinsic scatter (beyond measurement uncertainty) for the canonical He-models with proton-to-neutron ratio 1:1. We characterize temperature sensitivity by a temperature scale $T_0$ in model-agnostic power-law relations with temperature normalized radius. For low-mass WDs, the results identify a remarkably modest $T_0 = 1 \sim 2 $ eV. We comment on a potential interpretation for atmospheres insulating super-Eddington temperature cores from the sub-Eddington photospheres of low-mass WDs.

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Jin Lim, Ji-Yu Kim, Maurice H. P. M. van Putten. 2024-08-26. A temperature scale of $1\sim2$ eV in the mass-radius relationship of white dwarfs of type DA. https://arxiv.org/abs/2408.15291

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