'Super Earth' has rocky surface, say astronomers

Sydney, August 7 (ANI): European astronomers have said that the smallest planet yet detected outside our Solar System, dubbed 'Super Earth', appears to have a solid surface.

According to a report by ABC News, the European team describe the exoplanet CoRoT-7b, a so-called Super-Earth, which has a diameter approximately twice that of Earth.

The astronomers say the planet orbits its star once every 20 hours, making it the shortest orbital period yet detected.

Because of its close proximity to the star, it has a surface temperature between 1000 degrees Celsius and 1500 degrees Celsius and does not appear to have a significant hydrogen atmosphere.

The team said that the exoplanet's size and mass are compatible with it having a rocky surface.

CoRoT-7b was detected more than a year ago using the French COROT telescope, which orbits about 900 kilometres above the Earth.

It detects exoplanets by measuring the dimming of light that occurs as a planet transits across its parent star.

The team spent the past year using ground-based telescopes, including the Anglo-Australian Telescope in north-western New South Wales, to confirm the find.

According to Professor Chris Tinney, of the Department of Astrophysics at the University of New South Wales, the European team's findings are interesting because they indicate the planet's surface is rocky.

He said that most of the 300-plus exoplanets discovered to date are "so massive that we expect them to be gas or ice giants like Jupiter, Saturn, Uranus and Neptune".

"Others planets have small masses, but we have no idea what their sizes are and so we don't know their densities," Tinney added.

He said that the length of the transit provides valuable information on the size of CoRoT-7b.

"Having a mass of up to five to eleven times that of the Earth, would suggest that the planet is indeed likely to be one with a rocky nature," said Tinney. (ANI)