omg delta-Scuti stars

In the MPIA stellar physics group meeting today, in what might be the best seminar I have ever heard about the Kepler data, Simon J. Murphy (Sydney) told us about things he has been doing with delta-Scuti variable stars. There were so many results in his 30-minute discussion I can't even name them all here, but here are some highlights: delta-Scuti stars have such high coherence (Qs in the 105 or 106 range, or maybe even higher) that they are almost as good as pulsars as timing standards. By timing the stars, you can see binaries, and he has found hundreds of binaries. He can measure the binary parameters in the timing of every one of multiple modes! But there are some binaries where you can see the asteroseismic modes of both stars in the binary! Like double-lined spectroscopic binaries, these are double-moded asteroseismic binaries. Insane, and incredible tests of stellar physics. But that's not all: He has some that are even transiting too, to test radius models and more. Among his binaries are brown dwarfs, but also a few planets. One of these is a habitable-zone planet in orbit around an A-type star! That's a first, and very good for habitability, because it is near the triple-point for water but also has lots of blue photons for life-giving free energy! He showed eccentricity and period distributions for binaries, showing evidence for circularization at small radii and also showing posterior inferences about binaries at periods much longer than the Kepler mission lifetime. So. Many. Things.

In addition to this, Mia Lundkvist (LSW Heidelberg) gave a pedagogical introduction to asteroseismology and showed her evidence that super-Earths are getting ablated or destroyed or stripped when they are very close to their host stars. I spent the afternoon reading and editing in Dan Foreman-Mackey's latest draft for his long-period planet paper.

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