Jim Fuller edited Magnetic Constraints.tex  almost 9 years ago

Commit id: 185af34bc3d13e92f1d142ceb5f334a053568937

deletions | additions      

       

%The critical field strength $B_c$ is dependent on wave frequency, and lower frequency waves are more susceptible to magnetic suppression.  For a given field strength, there is a transition frequency $\nu_c$ below which modes will be strongly suppressed and above which modes will appear normal. Stars which show this transition are especially useful because they allow for an {\bf inference} of $B$ at the H-burning shell via equation \ref{eqn:Bc}, evaluated at the transition frequency $\omega = 2 \pi \nu_c$. {\bf The RGB star KIC8561221 shows this transition (\cite{Garcia_2014}). \cite{Garcia_2014}.  Using the observed value of $\nu_c \approx 600 \, \mu{\rm Hz}$, we infer that the radial component of the magnetic field within the H-burning shell is $B \approx 1.5 \times 10^{7} \, {\rm G}$, although we cannot rule out the presence of stronger fields away from the H-burning shell}. This large field strength may indicate KIC8561221 is the descendant of a magnetic Ap star whose internal field was much stronger than the typical surface fields of $B \sim 3 \, {\rm kG}$ of Ap stars (\cite{Auri_re_2007}). \cite{Auri_re_2007}.