Men who stare at stars

Six hours from Cape Town, in the hills near Sutherland, are astronomical telescopes that have been crucial in finding other solar systems, and that have made huge contributions to the search for earth-like planets orbiting distant stars.

This year a new telescope at Sutherland is expected to play an important role in discovering more about exoplanets.

Researchers at the SA Astronomical Observatory have partnered with Nova, a research fund in the Netherlands, and Leiden University in the Netherlands, to study the star Beta Pictoris and one of its planets, Beta Pictoris b.

Using a set-up the size of a washing machine, and what they have learned from observing the Beta Pictoris system, Matthew Kenworthy and Steven Crawford have developed theories about how giant gaseous planets such as Jupiter and Saturn form, and what that means for finding earth-like planets.

"If we look at gas giants in our solar system and the moons that orbit them, we don't know how they formed or how they got where they are. By looking at Beta Pictoris and its planet we are looking at a very early baby photo, which ideally will tell us how these planets form," Kenworthy said.

Astronomical researchers have long used this star as a typical example of a young star, but in 1981 it began to flicker, mystifying observers.

Kenworthy and Crawford believe that the flickering is caused by giant gaseous clouds moving in front of the star and intermittently dimming its light.

From the movements of the clouds the two will be able to determine their constituents and how they contributed to forming both the planet Beta Pictoris b and its moons.

"We can't see the planets of Beta Pictoris because they are too small, but it's possible to see the star dim a bit as the gaseous cloud around Beta Pictoris b moves in front of it.

"We don't know which stars have planets around them, so all we can do is look at as many stars as possible as often as possible for those flickers," Kenworthy said.

Nightly their observatory turns its scope, comprising two commercial camera lenses, on Beta Pictoris. The cameras track the star and measure the intensity of the light it emits. Every six seconds a photograph is taken - that's over 5000 images a night.

From these images Kenworthy and Crawford can determine whether the gaseous clouds are important in planetary and moon formation.

Beta Pictoris b is too large to harbour life but Kenworthy has hope for its moons.

"Beta Pictoris is much larger than any planet in our solar system, so its moons might be big enough to hold an atmosphere," Kenworthy said.

"The big question all of us are trying to answer is where did we come from," Crawford said. "By looking at the atmospheres of other planets we can see how things evolved."