Jim Fuller edited subsection_Measurements_Uncertainties_and_varepsilon__.tex  almost 9 years ago

Commit id: 597057f180d3c9093ea62738f6ca6a237fba8b8f

deletions | additions      

       

Most of the observational data shown in Figure \ref{fig:moneyplot} were obtained from \cite{Mosser_2012}. The additional stars KIC 8561221 and KIC 9073950 were analyzed using the same methods as \cite{Mosser_2012}. This analysis provided measured values of dipole mode visibility $V^2$, $\nu_{\rm max}$, $\Delta \nu$, and their associated uncertainties. For KIC 9073950, we used the updated KIC $T_{\rm eff}$ \citep{2014ApJS..211....2H} to calculate mass and its uncertainty from scaling relations. For KIC 8561221, mass and uncertainties were obtained from \cite{Garcia_2014}. To calculate values of $B_c$ for KIC 8561221 and KIC 9073950, we interpolated in $\log B_c$ between the tracks shown in Figure \ref{fig:Bc}, using the measured stellar masses. The uncertainty in $B_c$ was obtained by performing the same interpolation on the upper and lower bounds of the stellar mass.     {\bf We note that the red giant $\varepsilon$ Ophiuchi may also exhibit depressed dipole modes. Its temperature of $\approx 4900 \, {\rm K}$, inferred mass of $1.85 \pm 0.05 \, M_\odot$ and interferometricly measured radius of $10.39 \pm 0.07 \, R_\odot$ \cite{Mazumdar_2009} yield $\nu_{\rm max} \approx 57 \, \mu{\rm Hz}$ and $\Delta \nu \approx 5.5 \, \mu{\rm Hz}$. This is consistent with the interpretation (\cite{De_Ridder_2006,Barban_2007,Mazumdar_2009}) that many of the peaks in its {\emph MOST} power spectrum belong to a series of radial oscillation modes. However, we agree with \cite{Kallinger_2008,Kallinger_2012} that the most likely explanation for the power spectrum is that it is created by a combination of both radial and non-radial modes. We speculate that the low amplitude and missing dipole modes can be explained if $\varepsilon$ Ophiuchi is a depressed dipole mode star. At this stage of evolution, we expect the normalized depressed dipole mode power $V^2$ and lifetime $\tau$ to be roughly half their usual values, which may be consistent with the values. The  measured life times of $\tau \sim 12 \, {\rm days}$ (\cite{Kallinger_2008}). (\cite{Kallinger_2008}) are dominated by radial and envelope-dominated quadrupole modes, and are consistent with the usual lifetimes of these modes in red giants at this stage of evolution.  A more robust conclusion would require a comparison of measured radial mode linewidths to dipole mode linewidths, and our scenario would predict that the dipole modes should have lifetimes of $\tau \sim 6 \, {\rm days}$. We suspect that overlapping radial and quadrupole modes may help explain the large linewidths found by \cite{Barban_2007}, who considered the peaks to be produced solely by radial modes.}