Identifying White Dwarf Binary Systems with Spectral Energy Distributions
Dr. Todd Hillwig
Arts and Sciences
The Department of Physics and Astronomy
A white dwarf is formed from the leftover core of a sun-like star. Eventually, sun-like stars expand such that they can engulf a nearby companion, creating a common envelope around the star's core and the companion. This causes the orbit between these stars to tighten and ejects this common envelope into space, leaving a binary system consisting of a hot white dwarf and the companion in a very close orbit. We seek to identify these binary systems in order to determine the fraction of white dwarfs in binary systems, and to allow later investigations of their physical parameters. This will allow for a better understanding of the common envelope phase and the binaries that result from them. From a list of 112 hot white dwarf targets, we use spectral energy distributions to search for possible binary systems. We performed a preliminary blackbody fit, identifying 22 binary candidates. Using synthetic spectra, which include stellar atmosphere absorption features, we perform a more precise fit, which also corrects for reddening and extinction. With these, we find 16 binary candidates. We then determine whether there appear to be any additional other stars near our target that may be contaminating the data. Four of the 16 candidates did not appear to be encroached by additional light. All four have been identified as binaries by other researchers. We discuss the likelihood of the remaining 12 being true binary systems. Based on our results we also discuss implications for the binary fraction of the sample.
Gilles, Nicholas, "Identifying White Dwarf Binary Systems with Spectral Energy Distributions" (2023). Summer Interdisciplinary Research Symposium. 152.