a.k.a. John Southworth

My homepage contains more details, my publications list, useful codes, and other resources for detached binary stars.

I am currently a postdoctoral research fellow at the University of Warwick, UK, working with Dr Boris Gänsicke and Prof Tom Marsh. My research in astrophysics currently concentrates on two types of binary star system: detached eclipsing binaries and cataclysmic variables.

Detached eclipsing binaries are vital to our basic understanding of stars, galaxies and the Universe, because they are pretty much the only stars for which we can accurately measure such fundamental properties as mass, radius and temperature. This allows us to derive precise ages and metal abundances, and to improve theoretical models of stars. Detached eclipsing binaries which are members of stellar clusters are particularly useful, because they give the age, distance and metal abundance of the cluster and because the cluster data can be combined with the binary data to give more severe tests of theoretical model predictions.

Cataclysmic variables are a particular type of interacting binary system where a white dwarf, which is the extremely dense core of what used to be an evolved star, is pulling matter from a low-mass unevolved companion star. This results in an accretion disc and lots of nasty, poorly-understood, physical phenomena. It is important to understand this process because it occurs in many of the most extreme and luminous objects in the Universe, e.g. quasars and black holes. These phenomena are thought to be the cause of incredibly powerful gamma-ray bursts but these ideas are still being thrashed out by the astronomical community.