Researchers Identify Planets Where a Year is Only a Few Short Hours

When a team of scientists led by researchers from Massachusetts Institute of Technology set out to find planets with short orbital periods, they weren't sure what they would find.

"We've gotten used to planets having orbits of a few days," Josh Winn, an associate professor of physics at MIT, said in a press release. "But we wondered, what about a few hours? Is that even possible?"

Turns out, it is.

Through the help of NASA's planet-hunting Kepler space telescope, among other things, Winn and his colleagues were able to identify a planet that orbits its sun in just over eight hours and a second in roughly half of that.

The first, known as Kepler 78b, is roughly the size of Earth and boasts an orbital radius only three times the radius of the star and, scientists estimate, a surface temperature as high as 3,000 degrees Kelvin, or more than 5,000 degrees Fahrenheit. If this is the case, it's likely that the planet's top layer is comprised of one heaving ocean of lava.

Kepler 78b is especially exciting, according to the researchers, due to the presence of detectable light emitted from its surface -- a first for an exoplanet of its diminutive size. Once analyzed through larger telescopes, the researchers hope this light will offer greater details into important information such as the planet's surface composition and reflective properties.

Furthermore, because it is located so close to its star -- roughly 40 times closer than Mercury is to our sun -- the scientists hope to measure the planet's gravitational influence on it and thus the planet's mass. Should they prove successful, the discovery would mark the first time researchers would have managed to determine the mass for an exoplanet as small as Kepler 78b.

The other, known as KOI 1843.03, is believed to be made nearly entirely of iron based on its ability to withstand the massive tidal forces from the nearby star that would rip anything less dense to pieces.

"Just the fact that it's able to survive there implies that it's very dense," Winn said. "Whether nature actually makes planets that are dense enough to survive even closer in, that's an open question, and would be even more amazing."