Most Earthlike planet may be more like volcanic Jupiter moon Io

Washington, Feb 6 (ANI): A study has suggested that CoRoT-7b, which is the most Earthlike world yet found outside our solar system, may really be the first in a new class of exoplanets known as a "super-Io", like the volcanic Jupiter moon.

CoRoT-7b is considered to be the most Earthlike world yet found outside our solar system.

It was found using the French-led planet-hunting mission CoRoT, which looks for periodic dips in starlight caused by orbiting bodies passing in front of-transiting-a star, as seen from Earth.

When CoRoT-7b's discovery was announced in February 2009, astronomers hailed the world as the smallest exoplanet yet found orbiting a sunlike star.

But now, according to a report in National Geographic News, a recent study has suggested that Earth might not be the best basis for comparison for this planet.

Instead, the authors argue, CoRoT-7b is the first in a new class of exoplanets: a super-Io.

Like Jupiter's moon Io, CoRoT-7b could easily be in the right kind of orbit to experience what's known as tidal heating, according to study co-author Rory Barnes of the University of Washington in Seattle.

Barnes and colleagues looked at the possible orbits for CoRoT-7b based on its size and mass, its proximity to its star, and its interactions with a nearby sister planet, CoRoT-7c.

The researchers found that even a slight eccentricity in CoRoT-7b's orbit would generate enough tidal heating to spawn bunches of volcanoes, making the planet much more Io-like than Earthlike.

On Io, tidal heating is a result of the crust being constantly deformed by the push and pull of Jupiter's gravity.

"This action generates enough internal heat to drive hundreds of active volcanoes-and the same could be true for CoRoT-7b," Barnes said.

But unlike Io, CoRoT-7b closely orbits a star, not a planet, so tides aren't its only source of heat.

Based on previous observations, astronomers know that CoRoT-7b's surface is between 1,832 and 2,732 degrees Fahrenheit (1,000 and 1,500 degrees Celsius).

That's hot enough for there to be "ponds or possibly even oceans of magma," Barnes said.

Scientists also know that the planet is tidally locked, which means that only one side ever faces the star.

"There could be volcanism on the back side of the planet. It could be that on one side the surface is molten, and on the other side there's raging volcanoes," Barnes said. (ANI)