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Meredith L. Rawls added Introduction.tex almost 10 years ago

Commit id: 9cae471cb6b8736a48ec56dd9f66dd011acf9d6f

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% big picture context Mass and radius are often-elusive stellar properties that are critical to understanding a star's past, present, and future. Eclipsing binaries are the only astrophysical laboratories that allow for a direct measurement of these and other fundamental physical parameters. Recently, however, observing solar-like oscillations in stars with convective envelopes has opened a window to stellar interiors and provided a new way to measure global stellar properties. Asteroseismic scaling relations are an empirical connection between these oscillations, effective temperature, mass, and radius \citep{kje95,hub10,mos13}. While these relations are useful, they remain relatively untested. One notable exception is the red giant in the eclipsing binary KIC 8410637, which shows preliminary good agreement between Keplerian and asteroseismic mass and radius \citep{fra13}. In this work, we consider another archetypal case: KIC 9246715, an eclipsing binary composed of one oscillating red giant and one non-oscillating red giant with otherwise similar properties. % asteroseismology w/Kepler is an awesome tool Stars with convective outer layers potentially exhibit solar-like oscillations. These oscillations depend on the physical processes in their interiors. In particular, evolved red giants are increasingly easy to characterize through these pressure-mode oscillations \citep[for a review of this topic, see][]{cha13}. Compared to main-sequence stars, red giants pulsate with larger amplitudes and longer periods---several hours to days instead of minutes. Pulsations appear as spikes in an amplitude spectrum of a light curve that is sampled both frequently enough and for a sufficiently long duration. Given these two requirements, observations from the \emph{Kepler} space telescope taken every 29.4 minutes (long-cadence) over many 90-day quarters are ideal for asteroseismic studies of red giant stars. % EBs are really awesome w/Kepler too \emph{Kepler}'s primary science goal is to find Earth-like exoplanets orbiting solar-like stars \citep{bor10}. However, in addition to successes in planet-hunting suitability for red giant asteroseismology, \emph{Kepler} is also incredibly useful for studies of eclipsing binaries. In particular, \emph{Kepler} has discovered numerous long-period eclipsing systems from consistent target monitoring over several years. Eclipsing binary stars are extremely important tools for understanding fundamental stellar properties, and in turn for testing stellar evolutionary models or determining distances. When high-quality radial velocity curves exist for both stars in an eclipsing binary, along with a well-sampled light curve, a full orbital solution can be found. Accurate masses and radii are straightforward to derive from such a solution; indeed, Kepler's third law applied in this way is the \emph{only} direct method for measuring stellar masses. Taken together, red giants in eclipsing binaries (hereafter RG/EBs) that exhibit solar-like oscillations are an ideal testbed for the asteroseismic scaling relations. There are presently 15 known RG/EBs that show solar-like oscillations \citep{gau13,gau14}. All of these have relatively long orbital periods (tens to hundreds of days) and are found in the \emph{Kepler} field of view. % Overview of paper In this paper, we present physical parameters for the unique RG/EB KIC 9246715, which contains two red giant stars in a 171.3--day orbital period. Interestingly, only one of the stars shows solar-like oscillations, and with a lower amplitude than expected. \textbf{We find good agreement} between eclipsing binary models and asteroseismology for this system, and we explore how the likely presence of star spots and tidal effects influences the presence of oscillations. In \S \ref{data}, we describe how we acquired and processed photometric and spectroscopic data, and \S \ref{rvs} explains our radial velocity extraction process. In \S \ref{atm}, we disentangle each star's contribution to the spectra to perform stellar atmosphere modeling. We then present our final orbital solution and physical parameters for KIC 9246715 in \S \ref{model}. In \S \ref{discuss}, we compare our results with those from asteroseismology \citep{gau14} and discuss the possible connection between solar-like oscillations and effects such as star spots and tidal forces. Finally, \S \ref{conclude} summarizes our main results. % The above is written assuming that the masses and radii agree!!!