Helium at white dwarf photospheric conditions: preliminary laboratory results

TL;DR

This study reports preliminary laboratory measurements of helium under white dwarf photospheric conditions using the Z-machine, aiming to improve atmospheric models and theoretical understanding of helium behavior in extreme environments.

Contribution

First experimental measurements of helium at white dwarf photospheric conditions, aiding model validation and theoretical development.

Findings

Helium pressure shifts measured at various temperatures and densities.

Data can validate and improve white dwarf atmosphere models.

Guides development of new continuum-lowering theories for two-electron atoms.

Abstract

We present preliminary results of an experimental study exploring helium at photospheric conditions of white dwarf stars. These data were collected at Sandia National Laboratories' Z-machine, the largest x-ray source on earth. Our helium results could have many applications ranging from validating current DB white dwarf model atmospheres to providing accurate He pressure shifts at varying temperatures and densities. In a much broader context, these helium data can be used to guide theoretical developments in new continuum-lowering models for two-electron atoms. We also discuss future applications of our updated experimental design, which enables us to sample a greater range of densities, temperatures, and gas compositions.