Supervisor: Dr. Ian Stevens

The search for and the study of extrasolar planets will be one of the major challenges facing astrophysics over the next few years, and one which will have a profound impact on our understanding of our place in the Universe. Many important questions, like how common are planets, how common are "habitable" planets (and indeed what does "habitable" mean) and so on, remain to be answered.

There are projects in a number of areas available at the University of Birmingham.

1) Transiting extrasolar planets and stellar variability

We are currently using the HI instruments on the two STEREO satellites to investigate a wide range of stellar variability and to hunt for extrasolar planets via transits. Although these instruments were primarily designed to look for "Space Weather" events, such as coronal mass ejections, they provide CCD images of large portions of the sky, enabling the photometric monitoring of many stars.

As part of this project we will obtain long-term light curves of lots of stars, which will yield important new information. In addition to extrasolar planets we are investigating stellar pulsations (both solar-like oscillations, Cepheid variability and semi-regular variables) and a range of eclipsing binaries.

Work in this area will involve ongoing development of the data pipeline and also analysis of the stellar lightcurves. Development of algorithms to classify these lightcurves in an automatic manner is also a possibility.

This work is being done in conjunction with Bill Chaplin and Yvonne Elsworth from the BISON group.

2) Magnetospheric radio emission from extrasolar planets, brown dwarfs and related objects

Extrasolar planets are expected to emit low frequency radio waves, in the same way that Jupiter (or its magnetosphere) is a bright low frequency source. Because extrasolar planets are more distant, they are difficult to detect. We have already investigated the scaling of radio emission, depending on the distance of the planet from the star, mass of the planet etc, and made predictions about the levels of expected radio emission. One prediction is that exoplanets should be detectable using the upcoming Low-Frequency Array (LOFAR), a low-frequency radio telescope array, operating in the frequency range of 30-200MHz currently being constructed in Holland. The detection of emission from extrasolar planets will allow us to investigate extrasolar planets in novel ways, such as determining the magnetic field strength of the planets (important in understanding their internal structure), rotation rate, presence of moons and so on.

This project will involve both theoretical studies of the expected emission from extrasolar planets, using improved descriptions of the planetary and stellar properties and observations of the low frequency emission.

The emission mechanism for low frequency radio waves from extrasolar planets is the electron-cyclotron maser (ECM), a process involving the emission from electrons in the radiation belts of the planets. Planets are not the only source of ECM radiation, and it is believed that brown dwarfs (or at least some brown dwarfs) also show ECM emission. Other sorts of magnetic stars also probably show such radio emission, though how common it is remains uncertain.

We have a developing program to observe and study the radio emission from brown dwarfs and related objects (such as CU Virginis). This project will involve undertaking observing trips to the GMRT telescope in India as well as data from the E-Merlin array and also the eVLA.

For more information please contact Dr. Ian Stevens (Email: irs[at]star.sr.bham.ac.uk)