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Astrophysical and Planetary Sciences Colloquium
Monday, September 11, 2017 at 4:00 PM JILA Auditorium Keivan Stassun, Vanderbilt University "The Royal Road, Redux: Eclipses and Transits in the Era of Gaia and TESS"  Abstract:In his 1946 inauguration of the lectureship that now bears his name, Henry Norris Russell described eclipses as a "royal road" that "repays its followers richly." I begin by summarizing results from a number of rare, but astrophysically important eclipsing binary stars, that have paid richly in our understanding of (i) the effects of magnetic activity on the physical structure of low-mass stars and brown dwarfs, (ii) the role of triple systems in the formation and evolution of binaries, and (iii) the physics of surface convection in stars and its relation to stellar angular momentum evolution. Next, I describe how eclipsing binary stars serve as independent, empirical benchmarks for trigonometric parallaxes---with an accuracy of 200 micro-arcseconds or better that does not degrade with distance---and show an application of such a test to the first Gaia parallaxes (spoiler: there are some problems, but not too bad). I then describe an approach by which the Gaia parallaxes, together with observations of planetary transits of stars, permit the radii and masses of stars and planets to be measured with an accuracy of better than 5%, in an entirely empirical fashion. Already with the first Gaia parallaxes it is possible to assess the true masses of evolved planet-host stars (spoiler: they are mostly massive stars). I briefly summarize key results from the KELT transit survey and its implications for the science yield from the upcoming TESS mission specifically for massive stars, which are underrepresented in current planet surveys. Finally, returning to Henry Norris Russell's famous H-R diagram as an example, I conclude with some remarks on the role of data visualization in scientific discovery, and describe new efforts to quantify neuro-diverse visuo-cognitive capabilities in order to teach humans and machines to visualize data autistically.
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