FNWI --- IMAPP Department of Astrophysics
Radboud University > Faculty of Science > Department of Astrophysics

Compact binaries and type Ia Supernovae

Stars end their lives as compact objects: either white dwarfs (comparable in size to the Earth), neutron stars (comparable in size to a city, 10km) or black holes. Because most stars are born as member of a binary, there are many double stars containing one or two compact objects. These “compact binaries” are interesting laboratories of extreme physics and interesting as probes of the evolution of stars and their mutual interaction. Their formation traces exotic phases of binary stellar evolution and in many compact binaries matter is being transferred from the companion star onto the compact star. As the matter falls into the potential well of the compact star it is heated to temperatures of several million degrees. This leads to the release of very large amounts of energy, seen as emission of strong UV and X-ray radiation, and to the ejection of matter through very powerful jets. Their special evolution makes them powerful probes of stellar evolution, and the formation of black holes and neutron stars. Some of the white dwarfs in binaries evolve to explode as type Ia supernovae.

Group Members

Research topics

There are several research topics studies in our group

White Dwarfs and the Galaxy

Most stars end their lives as white dwarfs. In addition, after their formation white dwarfs cool down slowly, providing a way to study the extended history of the galaxy and the interactions in binary stars. Read more...

Type Ia Supernovae

Type Ia supernovae are exploding stars that are used to measure the accelerated expansion of the Universe and are responsible for most of the iron ever produced. Although there is general agreement that the exploding star is a white dwarf in a binary system, the exact configuration and trigger of the explosion is unclear. Two families of progenitor models have been proposed, one in which a white dwarf slowly gains mass from a companion and one in which two white dwarfs merge. We work on understanding if either (or both) of these models are correct. Read more...

X-ray binaries

X-ray binaries are binary stars, where one of the companions is either a neutron star or a black hole. Gas from the normal star is flowing towards the compact companion and is accreted. In the department of Astrophysics we are involved in research about the accretion process itself as well as the population and evolution of X-ray binaries. Read more...