My research covers a broad range of topics in astrophysics, from the physics of matter at high temperatures and densities to galactic structure and cosmochronology. The study of white dwarf stars is at the center of this work. Our group has developed an entirely new area of research: at-parameter experimental astrophysics. This research led to the creation of the Wootton Center for Astrophysical Plasma Properties as of 15 Feb 2018. Its purpose is to do experiments on plasmas under astrophysical conditions: we do at-parameter experiments not scaling experiments. We are currently exploring astrophysical plasmas under solar interior, supermassive black hole accretion disks, and white dwarf star photospheres. At Sandia National Laboratories (SNL), we create plasma under the same conditions we find in the cosmos. We make the first macroscopic (37 cubic centimeters) white dwarf photospheric plasmas on Earth. We have carried out more than 90 shots on the Z-machine at SNL in Albuquerque. We are using spectra of these plasmas to measure the line profiles of hydrogen plasmas under white dwarf photospheric conditions. We are working with SNL to help develop ways to measure the plasma conditions independently to calibrate model profile calculations. Currently, the line profile fits to the spectroscopic observations suggest unphysical low masses of white dwarf stars at all temperatures, when compared to our gravitational redshift measurements. Our experimental work resolved problems across many disciplines such as white dwarf cosmochronology and white dwarf stars used as dark matter and extrasolar planet detectors. We has also carried out a theoretical analysis of line broadening that matches observation and experiment much better, and we have included this in a stellar atmosphere code for direct comparison with our spectroscopic astronomical observations using the HET. This is the first new treatment of line-broadening since the 1970s, and greatly advances the state of the art in atomic physics as well as astrophysics. Most recently, it has been shown that neutral broadening in He is theoretically under-estimated.