Astronomers find higher incidence of 'hot Jupiters' in star clusters

A team of astronomers using data from the La Silla observatory in Chile found that planets known as "hot Jupiters" are more common in a star cluster in the constellation of Cancer than around stars outside clusters.

Hot Jupiters are exoplanets - planets outside the Solar System - that have at least 36 percent the mass of Jupiter and are much closer to their respective parent stars than Jupiter is to the Sun.

A hot Jupiter's orbital period is less than 10 days, while the original Jupiter takes the equivalent of 10 Earth-years to orbit the Sun, EFE reported.

The discovery was the result of years of work by scientists from Chile, Brazil and Europe, led by Roberto Saglia of Germany's Max-Planck-Institut and Luca Pasquini from the European Southern Observatory, which operates the La Silla installation.

The team collected high-precision measurements of 88 stars in Messier 67, a star cluster about the same age as the Sun.

"This is really a striking result," according to Anna Brucalassi, who carried out the analysis. "The new results mean that there are hot Jupiters around some 5 percent of the Messier 67 stars studied - far more than in comparable studies of stars not in clusters, where the rate is more like 1 percent."

Scientists think these giant exoplanets probably formed at a much greater distance from their stars and gradually moved closer, as was the case with Jupiter.

What astronomers are still trying to determine is what causes Jupiter and similar planets to move toward their respective stars.

--IANS

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