In The News South Africa

SA participates in international astronomy programme

CAPE TOWN, May 30– Astronomers from around the world, including South Africa, will attempt to study the rings of an exoplanet orbiting a star 63.4 light years away from earth.

The international programme, being conducted between April 2017 and January 2018, would have astronomers observing Beta Pictoris, the second brightest star in the constellation Pictor.

“Beta Pictoris is a star visible to the naked eye that has a large planet orbiting around it,” explained Dr Steve Crawford from the South African Large Telescope (SALT), who spoke about South Africa’s involvement in the 200 day observation at the South African Astronomical Observatory (SAAO) in Observatory, Cape Town, on Saturday.

“This year the planet is expected to pass nearly in front of the star. If there are rings around the planet, we will have an excellent chance to detect them with how closely the planet is passing in front of the star.”

According to Crawford, Beta Pictoris was still a young star and could give astronomers a glimpse of what the early solar system may have been like.

“In particular, this might give us a chance to study how moons form around a planet which is a process that is not very well understood yet,” explained Crawford.

In 1981, the brightness of Beta Pictoris diminished, which made astronomers think there must have been a huge object passing in front of the star, then the giant planet Pictoris b, was discovered in 2008.

“We are hosting one of the telescopes at the Sutherland Observatory of the SAAO,” said Crawford.

A small robotic all sky monitor with two camera systems, named the Beta Pictoris b Ring project, would be dedicated to looking at Beta Pictoris at SAAO in Sutherland in the Northern Cape.

The b Ring monitor would take images, which would be analysed on a set of computers. If a change in brightness was detected, it would allow the triggering of a host of observations using larger telescopes and more advanced instrumentation to study the details of the suspected ring system in-depth.

UCT PhD student, Blaine Lomberg, would be responsible for the SALT spectroscopic follow-up if anything was detected.

“If we detect a change in the flux coming from Beta Pictoris, it would trigger follow-up observations from a number of different observatories including SALT.

“We are hoping to use the follow-up observations to determine the characteristics of the rings, like what they are composed of,” said Crawford.

Crawford further explained that the area immediately around the vicinity of the planet would only take 2.5 days to cross in front of the star, but the total area where rings might be detected would take 270 days to pass in front of the star.

“So we want to monitor over a full year to see if we detect any other changes due to the planet transiting the star,” said Crawford.

The project was being led by Matt Kenworthy from Leiden University in the Netherlands, and the team also included a United States group that would be installing another monitoring station in Australia.

According to the National Aeronautical and Space Administration (NASA) in the United States, more than 3,000 exoplanets planets outside the solar system have been discovered since 1988.

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