Formation \& Evolution of Very Close and Contact Binaries

TYPEAstrophysics Seminar
Speaker:Ludmilla Kisseleva-Eggelton
Affiliation:Expression college, CA
Organizer:Hagai Perets
Time:11:30 - 12:30
Location:Lidow 620
Abstract:A surprising number of apparently unrelated processes are
necessary (but we believe also sufficient) for understanding
the formation, structure, evolution and long-term end-points
of contact binaries. The important processes are (a) hierarchical
contraction and fragmentation in a star-formation region, (b)
gravitational scattering of some systems off others, producing
triples with short-period sub-binaries, (c) Kozai cycles and
tidal friction, (d) magnetic braking also with tidal friction,
(e) energy transport within a contact envelope, (f) thermal
relaxation oscillations, and finally (g) a Darwin instability
that leads to a merger such as one observed in 2008.