Matteo Cantiello edited MAYBE_REMOVE_NEXT_PARAGRAPH_AND__.tex  almost 9 years ago

Commit id: 77addea94e11382cafc35702e5f12b2817ec8780

deletions | additions      

       

In Fig. 2 we show the %power ratio between dipole and radial modes (the  dipole mode visibility for about 3600 red giants observed over the first   37 months of the {\it Kepler} mission. Our analysis is restricted to stars with \numax\   larger than 50\muhz\ and masses below 2.1\msol, which ensures our sample is comprised almost entirely of it includes only  red giants that have not started burning helium in their cores. We verified this by cross matching our sample with those of known evolution state which showed only X helium burning stars in common, all of which had \numax\ below 70\muhz\ cores  \citep{Stello_2013,Mosser_2014}. %The missing dipole modes in a significant fraction of stars revented us using   %the dipole mode period spacings to select stars in this particular evolution stage  %\citep{Bedding_2011}.  

%A comparison with lists of helium core burning stars identified through measured period   %spacings of non-suppressed stars \citep{Stello_2013,Mosser_2014} revealed only X stars in common with our   %sample. They all had \numax\$ < 70\,$\muhz.   %It It  is striking how The the  stars form two distinct branches that gradually merge as the stars evolve towards lower \numax, \numax.  % This trend is also evident in Fig.1. with most Most  stars falling fall  on the ``normal'' upper branch of $V^2\sim 1.5$, in agreement with previous results \citep{Mosser_2011}.   The lower branch with suppressed dipole modes, agrees remarkably well with theoretical predictions (black curve) (Fuller et al. 2015). curve).  This reduction assumes that all the wave energy leaking into the stellar core is trapped. The {\bf According to Fuller et al. 2015, this occurs in stars with strong internal magnetic fields. For this branch} the  decrease of the suppression towards lower \numax\ is a consequence of the increasingly weaker coupling between acoustic waves in the envelope and gravity waves in the core as stars evolve (Fuller et al. 2015). With this large stellar sample we can separate the stars into five different mass intervals, represented in Fig.2 from 0.9 to 2.1\msol. It is striking how %, 2.1\msol,  which clearly shows that the relative population on the lower branch (stars with suppressed dipole modes) is strongly mass dependent.