When Flux Standards Go Wild: White Dwarfs in the Era of Space Photometry

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.

Speaker: JJ Hermes (Boston University)

All 2020 Spring Colloquia talks are held on Wednesdays in the STScI John N. Bahcall Auditorium at 3:00 p.m. preceded by tea at 2:45 p.m.

Please direct questions or comments to the contact above. The 2019-20 committee members are Paule Sonnentrucker (STScI Chair), Annalisa Calamida (STScI), Will Fischer (STScI), Ethan Vishniac (JHU Co-chair), Kevin Schlaufman (JHU), and Graeme Addison (JHU).