June 23, 2014

CoRoT decouvre un objet unique 06/10/2008

CoRoT découvre un objet unique

CNES's space telescope has discovered a new object so exotic that astronomers aren't sure whether to call it a planet. Named CoRoT-Exo-3b, the oddity is about the size of Jupiter, only 20 times more massive.

A small brown dwarf?

"We were taken by surprise when we found this massive object orbiting so close to its parent star", enthuses Magalie Deleuil from the LAM astrophysics laboratory in Marseille, who is leading the science team that made the discovery. She added, "CoRoT-exo-3b is really unique - we're still debating its nature."

In their near 15-year search for planets orbiting close to their parent star, astronomers have encountered a host of planets with masses up to 12 times that of Jupiter.

They have also found small stars 70 times as massive as Jupiter (the Sun is 1,000 times more massive than Jupiter), but none in between. Consequently, many scientists were beginning to think that no such objects existed.

CoRoT-Exo-3b exoplanet
CoRoT-Exo-3b is about the size of Jupiter but much more massive. Credits: OAMP

Science team member Dr Hans Deeg, from the IAC astrophysics institute in the Canary Islands, explains why this new object is such an important find for planet hunters:

"It could also be a very small brown dwarf, a failed star not massive or hot enough to shine like a normal star. We're not sure where to draw the boundary between planets and brown dwarfs. But no object has ever been found so close to that boundary, until now."

A new family of planets

Exoplanets transiting
Exoplanets transiting in front of their parent star. Credits: ESA/Ill. AOES Medialab.

"As a planet, CoRoT-Exo-3b would be the most massive and the densest found to date - more than twice as dense as lead," says Magalie Deleuil. "How did such a massive object form so close to its parent? That's a question we're now going to have to answer"

"CoRoT-Exo-3b might turn out to be a rare object found by sheer luck," said another science team member, Dr Francois Bouchy, from the IAP astrophysics institute in Paris, currently working at the Haute Provence observatory.

"But it might just be a member of a new-found family of very massive planets that encircle stars more massive than our Sun. We're now beginning to think that the more massive the star, the more massive the planet," he said.