Reaching Higher Densities for Laboratory White Dwarf Photospheres to Measure Spectroscopic Line Profiles [SSA]

http://arxiv.org/abs/1609.09101


As part of our laboratory investigation of the theoretical line profiles used in white dwarf atmosphere models, we extend the electron-density ($n_{\rm e}$) range measured by our experiments to higher densities (up to $n_{e}\sim80\times10^{16}$ cm$^{-3}$). Whereas inferred parameters using the hydrogen-$\beta$ spectral line agree among different line-shape models for $n_{\rm e}\lesssim30\times10^{16}$ cm$^{-3}$, we now see divergence between models. These are densities beyond the range previously benchmarked in the laboratory, meaning theoretical profiles in this regime have not been fully validated. Experimentally exploring these higher densities enables us to test and constrain different line-profile models, as the differences in their relative H-Balmer line shapes are more pronounced at such conditions. These experiments also aid in our study of occupation probabilities because we can measure these from relative line strengths.

Read this paper on arXiv…

R. Falcon, J. Bailey, T. Gomez, et. al.
Fri, 30 Sep 16
42/75

Comments: 6 pages, 2 figures, to appear in the proceedings of the 20th European Workshop on White Dwarfs held July 25-29th, 2016 at the University of Warwick, United Kingdom