Irish research groups are among the world leaders in the discovery and analysis of new exoplanets, writes RONAN MCGREEVY

THE DISCOVERY of the first exoplanet in 1995 has proved to be one of the greatest breakthroughs in astronomical history. Since then, nearly 450 more have been found and that number will rise expon- entially in the coming years.

We are beginning to realise that our planet and solar system are probably only one of billions in our own galaxy alone. The search is only beginning and yet the possibility of finding planets like ours draws ever nearer.

Queens University Belfast (QUB)'s Astrophysics Research Centre is a world-leader in discovering transiting exoplanets. These are planets that dim the light from their stars as they pass in front of them as we view them from Earth.

QUB is leading the northern hemisphere teams on the Wide Area Search for Planets project (SuperWASP), which detects transiting planets using cameras in the Canary Islands and South Africa. The team will receive the Group Achievement Award for Astronomy today at the Royal Astronomical Society in Glasgow.

The team has discovered 18 exoplanets to date despite existing on modest resources.

Most of the planets discovered so far have been "hot Jupiters", huge gas giants many times bigger than Jupiter which orbit close to their parent star. By understanding the laws of motion the SuperWASP team have been able to calculate the size and mass of many of these planets.

"We have found planets the size of Jupiter that are a lot lighter than Jupiter. They must be composed of materials that are much lighter than the material on Jupiter," said Prof Don Pollacco, the head of the team at QUB.

The process of looking for exoplanets is hard work involving the analysis of months' of data showing minute changes in the light from planets. "It is like having a small torch, putting it close to a stadium flood and see if you can see it a mile away," he explains.

"We're very lucky to be able to do this. People have been looking for planets around other planets for centuries and historically people have been burnt at the stake for this. To be in a position to do this, it is amazing what we can do. This is never routine. It is always hard work."

NUI Galway's Centre for Astronomy has the biggest group of academic astronomers in Ireland. They are working on three separate projects which could impact on the discovery of exoplanets.

They are developing the Galway Astronomical Stokes Polarimeter (Gasp), which they are going to put on ten metre-class telescopes in two years' time. "That can look at the polarisation signal from a planet orbiting a star. We expect the polarisation to change. We think it is a novel way of actually looking at aspects of the atmosphere of exoplanets," says Dr Andy Shearer, centre director. Dr Nicholas Devaney is working on adaptive optics to allow telescopes to see fainter objects such as exoplanets with the ultimate goal of being able to directly see exoplanets.

Another potentially exciting area of research is the work being done by Alastair McKinstry. He is attempting to model the potential climates of exoplanets especially "Super Earths", which are one- to 10-times the size of Earth, and what they might be like. "Within the next five years we expect to be able to discover the first Earth-sized planet," he says.

Shearer says the research into exoplanets has implications which go beyond the scientific even if we have no hope at present of ever visiting these planets. "One of the more fundamental aspects of modern science is to answer questions about, in essence, whether we are alone. In order to answer that question, we need to have an idea of the distribution of planets around different solar systems," he says.

Research being carried out at Cork Institute of Technology (CIT) and the Institute of Technology in Tallaght is designed to help astronomers search in the right places for exoplanets – and in a much narrower field of vision – which will allow them be seen more clearly. The Blackrock Castle Observatory (BCO) Planet Search Programme is a first in the world.

"I love the idea that it is Irish researchers and Irish students who are studying these problems and trying to come up with solutions, that it is not researchers at Harvard or Stanford doing these kind of things," said Dr Niall Smith of the Blackrock Castle Observatory team and head of research at CIT.