August 11, 2011

New Exoplanet Blacker Than Coal Discovered

Astronomers said on Thursday that they have discovered the darkest known exoplanet they say is the size of Jupiter.

The researchers said exoplanet, TrES-2b, is blacker than coal or any planet or moon in our solar system.

"TrES-2b is considerably less reflective than black acrylic paint, so it's truly an alien world," astronomer David Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA), lead author on the paper reporting the research, said in a statement.

TrES-2b lacks reflective clouds due to its high temperature. 

The planet has a temperature of over 1,800 degrees Fahrenheit and orbits its star at a distance of only three million miles.

"It's not clear what is responsible for making this planet so extraordinarily dark," co-author David Spiegel of Princeton University said in a statement. "However, it's not completely pitch black. It's so hot that it emits a faint red glow, much like a burning ember or the coils on an electric stove."

The team found TrES-2b by using data from NASA's Kepler spacecraft. 

The exoplanet is believed to be tidally locked like Earth's moon, so one side of the planet always faces the star.  The planet also shows changing phases as it orbits its star.

"By combining the impressive precision from Kepler with observations of over 50 orbits, we detected the smallest-ever change in brightness from an exoplanet: just 6 parts per million," Kipping said in a press release. "In other words, Kepler was able to directly detect visible light coming from the planet itself."

TrES-2b orbits the star GSC 03549-02811 about 750 light-years away in the direction of the constellation Draco. 

The researchers published their findings in the Monthly Notices of the Royal Astronomical Society.


Image Caption: The distant exoplanet TrES-2b, shown here in an artist's conception, is darker than the blackest coal. This Jupiter-sized world reflects less than one percent of the light that falls on it, making it blacker than any planet or moon in our solar system. Astronomers aren't sure what vapors in the planet's superheated atmosphere cloak it so effectively. Credit: David A. Aguilar (CfA)


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