Meredith L. Rawls edited Discussion.tex  almost 9 years ago

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Because both stars in KIC 9246715 are evolved giants with convective envelopes, we expect both to exhibit solar-like oscillations. These should be observable as p-modes in \emph{Kepler} long-cadence data. The average large frequency separation of such modes $\Delta \nu$ has been shown to scale with the square root of the mean density of the star, while the frequency of maximum oscillation power $\nu_{\rm{max}}$ carries information about the physical conditions near the surface of the star and is a function of surface gravity and temperature \citep{cha13}. These so-called scaling relations may be used to estimate a star's density and surface gravity:  \begin{equation} \label{density} %\label{density}  {\left( {\frac{\rho}{\rho_{\odot}}} \right)} \simeq {\left( {\frac{\Delta \nu}{\Delta \nu_{\odot}}} \right)}^{2}  \end{equation}  and  \begin{equation} \label{gravity} %\label{gravity}  {\left( \frac{g}{g_{\odot}} \right)} \simeq {\left( \frac{\delta \nu_{\rm{max}}}{\delta \nu_{\rm{max}, \ \odot}} \right)} {\left( \frac{T_{\rm{eff}}}{T_{\rm{eff}, \ \odot}} \right)}^{1.5}.  \end{equation}  However, when \citet{gau13} and \citet{gau14} analyzed the oscillation modes to estimate global asteroseismic parameters, only one set of modes was found. Of the 15 oscillating red giants in eclipsing binaries in the \emph{Kepler} field, KIC 9246715 is the only one with a pair of giant stars (the rest are composed of a giant star and a main sequence star). The oscillation spectrum is shown in Figure \ref{fig:seismo}. \citet{gau14} note that the mode amplitudes are low ($A_{\rm{max}} \simeq 6.6$ ppm), report photometric variability as large as 2\%, and speculate that star spots may be responsible for inhibiting oscillations on the smaller star. They also report $M = 2.06 \pm 0.13 \ M_{\odot}$ and $R = 8.10 \pm 0.18 \ R_{\odot}$ by rearranging the scaling relations in Equations \ref{density} and \ref{gravity}:  \begin{equation} %\label{radeq}  \left( \frac{R}{R_\odot} \right) \simeq \left( \frac{\nu_{\rm{max}}}{\nu_{\rm{max,\odot}}} \right) \left( \frac{\Delta \nu}{\Delta \nu_\odot} \right)^{-2} \left( \frac{T_{\rm{eff}}}{T_{\rm{eff,\odot}}} \right)^{0.5}  \label{radeq}  \end{equation}  and  \begin{equation} %\label{masseq}  \left( \frac{M}{M_\odot} \right) \simeq {\left( \frac{\nu_{\rm{max}}}{\nu_{\rm{max,\odot}}} \right)}^{3} \left( \frac{\Delta \nu}{\Delta \nu_\odot} \right)^{-4} \left( \frac {T_{\rm{eff}}} {T_{\rm{eff,\odot}}} \right)^{1.5}.  \label{masseq}  \end{equation}  It is important to note the strong temperature dependence of these relations. WRITE SOMETHING ABOUT NEW M AND R ESTIMATES WITH BETTER TEMPERATURE INPUTS HERE. COMPARE LOG G VALUES HERE TOO SINCE IT'S JUST TESTING NU-MAX AND NOT DELTA-NU.