Astrophysics Seminars

I will discuss two cases where models of protoplanetary discs developed for astrophysical application can help understand problems in cosmochemistry. In the first I will show how accretion bursts through the gravo-magnetic limit cycle can control...

The transport of angular momentum by magnetic fields is a crucial physical process in formation and evolution of stars and disks. Because the ionization degree in star forming clouds is extremely low, non-ideal magnetohydrodynamic (MHD) effects such...

Hot Jupiters constitute one of the many surprises of Exoplanet searches. Their tight, few-day orbits make them a challenge for commonly invoked planet formation scenarios and correspond to the onset of strong tidal dissipation. Hot Jupiters could...

No true extrasolar Earth analog is known. Hundreds of planets have been found around Sun-like stars that are either Earth-sized but on shorter periods, or else on year-long orbits but somewhat larger. Under strong assumptions, exoplanet catalogs...

The flow of disk material close to a planet, at separations of order r_H, the Hill radius, generates the largest transfer of angular momentum and mass between the planet and the circumstellar disk. For large, Jupiter-size planets, they typically...

B-type main-sequence (MS) stars (M = 3 - 16 Msun) with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, gamma ray bursts, and sources of gravitational waves. However, the formation...

Understanding whether Helium can sediment to the core of galaxy clusters is important for a number of problems in cosmology and astrophysics. For example, our ignorance in the distribution of Helium leads to systematic uncertainties in estimating...