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SUMMARY:Orbital Circularization of Binaries with Resonance Locking from St
 ellar Evolution - Dr. J. J. Zanazzi (CITA\, Toronto)
DTSTART:20191014T130000Z
DTEND:20191014T140000Z
UID:TALK129193@talks.cam.ac.uk
CONTACT:Chris Hamilton
DESCRIPTION:Although tidal dissipation in binary stars has been studied fo
 r over a century\, many theoretical predictions do not match the observed 
 properties of binary population orbits and rotation rates.  Both equilibri
 um and dynamical tidal theories predict different eccentricities at the or
 bital periods and ages binaries are observed in populations\, and many asy
 nchronously rotating binaries have ages longer than their calculated synch
 ronization times.  Motivated by these difficulties\, we investigate the or
 bital and rotational evolution of binaries driven by resonance locking\, a
  theory which argues most tidal dissipation occurs from resonances between
  the host's natural oscillation frequency (from gravity modes) and the per
 turber's tidal potential oscillation frequency\, locked by the entropy-pro
 file evolution of the host star.  We find orbital evolution via resonance 
 locking to efficiently circularize binaries out to 4-6 days during the pre
 -main-sequence\, and decrease the eccentricities of moderately and highly 
 eccentric binaries out to 100 days.  Binary evolution via resonance lockin
 g predicts the binary's synchronization time to be usually longer than the
  circularization time.  Resonance locking can potentially explain the ecce
 ntricity distribution of eccentric binaries out to 100 days\, but cannot e
 xplain the over-abundance of nearly-circular binaries out to 10 days.
LOCATION:MR14\,  Centre for Mathematical Sciences\, Wilberforce Road\, Cam
 bridge
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