A-F star mysteries as revealed by the NASA Kepler spacecraft

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Date/Time:Friday, 01 Nov 2013 from 4:10 pm to 5:00 pm
Location:Physics 0003
Contact:Le Anne Willson
Phone:515-194-1958
Channel:Astronomy
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Photo
Joyce Guzik (Los Alamos National Laboratory)

The NASA Kepler mission was launched in 2009 to search for planets around sun-like stars via planetary transits. The Kepler mission also provided the opportunity to observe thousands of stars with high-precision photometry for weeks to years. I will discuss observations of thousands of stars of spectral types A-F that were intended to discover and characterize pulsations in delta Scuti pulsating variables with periods of a few hours, and gamma Doradus variables, with periods of about a day. Before Kepler, the known variables appeared to fit within the instability regions expected from theory/simulation. However, Kepler has found stars pulsating in one or both types outside of their expected instability regions, as well as apparently non-pulsating stars within the instability regions. I will discuss the standard explanations for their pulsations, possibilities to explain the pulsating and non-pulsating stars, and implications for stellar physics. I will also show a sample of interesting light curves among those observed by Kepler as part of the Guest Observer program.