Speed demon: Artist's impression of the planet OGLE-TR-L9b. Circling its host star in about 2.5 days, it lies at only three per cent of the Earth-Sun distance from its star, making the planet very hot with a bloated, roiling atmosphere.
Credit: ESO/H. Zodet
LONDON: A massive exoplanet is the first yet found orbiting a super-hot, rapidly rotating star, which turns at around 12 times the speed of our Sun.
The planet, which orbits its star in just 2.5 days, is found at only three per cent of the distance between the Earth and the Sun.
With a surface temperature of over 6,600 ºC, this 'hot young star' is also the warmest ever know to have planets in orbit aroud it, said Ignas Snellen, who led a team of astronomers behind the discovery at the University of Leiden in the Netherlands. Our own Sun has a surface temperature of around 5,500 ºC.
Hot young star
Many far-flung exoplanets have been discovered in recent years, but so far none have been found with such an unusual partner star, say the researchers. Part of the reason is that the violent rate of rotation of hot young stars makes it more difficult to collect data on them.
"Many surveys may have missed other planets, because they often just 'throw out' results from these fast-rotating stars", said Snellen.
This latest discovery was made by Snellen's students who were developing an algorithm to more accurately detect the minute dimming that occurs when an exoplanet passes in front of its star.
To test the algorithm, the team applied it to unexplored data from the Optical Gravitational Lensing Experiment (OGLE) – a Polish project, based at Warsaw University, the main purpose of which was to use the microlensing technique to gather data on dark matter.
Ogling data
Within this data, the researchers saw a curious blip. One of the stars dimmed regularly for two hours every 2.5 days, suggesting a planet was whipping around the star in a remarkably tight, speedy orbit. "I was completely taken aback," Snellen told Cosmos Online.
On closer observation, his team found that an exoplanet around five times the size of Jupiter was tugging the star back and forth and dimming it marginally as it rotated every 2.5 days. They confirmed the presence of the planet, now called OGLE2-TR-L9b, by making observations with the European Southern Observatory's Very Large Telescope in Chile.
The research is slated for publication in the journal Astronomy and Astrophysics.
The discovery "should give people confidence in finding younger planetary systems," commented Andrew Collier Cameron, an astronomer from the University of St Andrews in Scotland who was not involved in the research. "Really, we should be paying more attention to [rapidly rotating hot young stars]," he said.
