Résumé / Abstract Seminaire_IAP
« Outbursts Around Dead Stars: How Dwarf Novae Are Testing Our Fundamental Fluid Dynamics Theory of Accretion Disks »

Omer Blaes
Physics Dept., Univ. California (Santa Barbara, California, Etats-Unis d'Amérique)

Dwarf novae are transient optical outbursts observed from close binary systems containing a white dwarf that is accreting material from a companion star. This accreting material takes the form of a differentially rotating disk around the white dwarf, a structure that is of wide-ranging importance in astrophysics, from protoplanetary disks around young stars to quasars and gamma-ray bursts. Understanding how angular momentum is transported and gravitational binding energy is dissipated is of fundamental importance to all these systems. Dwarf novae are somewhat special, however, in that their observed outbursts are caused by a thermodynamic instability in the disk with short recurrence times, allowing for exquisitely detailed and extensive observations of their variability. This variability has challenged our fundamental theories of angular momentum transport in accretion disks, and I will discuss recent progress in reconciling this theory with observations. This, in turn, has generated deeper appreciation of the complex nonlinear dynamics of these flows, with interesting physics puzzles that remain to be solved.
vendredi 26 février 2016 - 11:00
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage