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

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\end{equation}  These relations should be valid only for oscillation modes of large radial orders $n$, where pressure modes can be mathematically described in the frame of the in the ``asymptotic development'' (CITE TASSOUL 1980). Even though red-giant do not match these conditions, because radial orders of observed modes are less than 10, the scaling relations look to work rather well, but we ignore until what extent. This is why measuring masses and radii, independently from seismology, of stars where we observe oscillation modes is so important.  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 as well as its representation as an \'echelle diagram is are  shown in Figure Figures  \ref{fig:seismo} (I'LL SEND THE PLOTS). and \ref{fig:echelle}.  \citealt{gau14} reported that the oscillation pattern was typical of that of a star from the secondary red clump, i.e. a star that burns He in the core, without having experienced an He flash. The mode amplitudes are quite low ($A_{\rm{max}}(l=0) \simeq 14$ ppm, and not 6.6 as erroneously reported by \citealt{gau14}) with respect to the 20 ppm we expect based on the mode amplitude scaling relations (CORSARO ET AL 2013 MNRAS 430, 2313), and by supposing only one star oscillates. Besides, the light curve displays a significant photometric relative variability as large as 2\% peak-to-peak, which is typical of the signal created by spots on stellar surfaces. The pseudo period of this variability was observed to be about half the orbital period, which indicates resonances in the system. \citet{gau14} speculated that star spots may be responsible for inhibiting oscillations on the smaller star, as they observed on other five systems. We reestimated $\nu_{\rm{max}}$ and $\Delta\nu$ in the same way as \citet{gau14}, but by using the whole \textit{Kepler} dataset (Q0 to Q17). Differences with respect to previous estimates are minute but we keep the new ones as reference: $\nu_{\rm{max}} = 106.4 \pm 0.8$ and $\Delta\nu=8.31\pm0.01$. To determine mass, radius, surface gravity, and mean density, we use the scaling relations after correction of $\Delta\nu$ for the red-giant regime (CITE MOSSER 2013 A\&A 550, 126). In few words, instead of directly plugging the observed $\Delta\nu_{\rm{obs}}$ into the scaling equations, we estimate the asymptotic large spacing $\Delta\nu_{\rm{as}}$ as follows: $\Delta\nu_{\rm{as}} = \Delta\nu_{\rm{obs}} (1 + \zeta)$, where $\zeta = 0.038$. With this correction of the large spacing, and assuming $T_{\rm{eff}} = 5050 \pm 100$~K, we obtain: $M = 2.21 \pm 0.12 \ M_{\odot}$ and $R = 8.30 \pm 0.16 \ R_{\odot}$. In terms of mean density and surface gravity, which independently test $\Delta\nu$ and $\nu_{\rm{max}}$ relations respectively, we get: $\bar{\rho}/\bar{\rho}_{\odot} = (3.862 \pm 0.009)\ 10 ^{-3}$, and $\log g = 2.944 \pm 0.007$ dex.