Astrophysics Seminar – 17th Feb 3pm. JJ Hermes: White dwarf variability as seen from space

Please find a teams link in the Astrophysics Group > Seminars area.

Abstract: White dwarfs have been used as flux standards for decades, thanks to their staid simplicity. These endpoints of all low- and intermediate-mass stars are used as absolute calibrators for a range of science, including precision cosmology. In the era of space missions like Kepler, Gaia, and TESS, we now have exquisite limits on just how standard most white dwarfs are. While we can confirm that the vast majority (>95%) of white dwarfs are stable to better than 1% in the optical, I will explore the ways in which white dwarfs vary photometrically, including exciting and dramatic new ways discovered from space. Some of these new variability mechanisms can cause a white dwarf, on its own, to get more than 45% brighter in a matter of hours, and some are likely signposts of double-degenerate mergers.