»Tiny telescope spots giant planet 500 lightyears away«

A tiny telescope has spotted a giant planet circling a faraway star, using a technique that could open a new phase of planetary discovery, according to scientists.

A telescope with a 10.16 centimetre diameter, about the size that some backyard astronomers might use, tracked the periodic dimming of light from a bright star 500 light-years away. A light-year is about 10 trillion kilometres, the distance light travels in a year.

That dimming suggested the presence of a big planet regularly blocking out a small portion of the light as it passed between the star and Earth. Later observations by the huge Keck I telescope in Hawaii, which has a diameter of 10 metres, confirmed the find.

More than 100 such exoplanets, or planets orbiting a star other than our sun, have been found in the last decade, but most of these have been discovered by observing stars that have a characteristic wobble, indicating a planet is nearby.

The small telescope that found this latest planet is part of a network of modest instruments called the Trans-Atlantic Exoplanet Survey, known as TrES, which is designed to look specifically for planets orbiting bright stars, scientists said in emailed statements.

One statement from the Harvard-Smithsonian Centre for Astrophysics said the new find, using such a small telescope, "demonstrates that we are at the cusp of a new age of planet discovery".

The new planet, called TrES-1, is a gas giant about the size of Jupiter, located in the constellation Lyra ("the lyre").

It orbits its star about once every three days at a distance of just 6.437 million kilometres, much closer and faster than the planet Mercury goes around our sun, giving it a temperature of around 815.55 degrees Celsius.

"This discovery demonstrates that even humble telescopes can make huge contributions to planet searches," said Guillermo Torres of the Harvard astrophysics centre, who co-authored a study on the finding.

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