National Geographic News
An illustration of a molten alien world.

Magma may cover UCF-1.01, which orbits scorchingly close to its star, as shown in an artist's concept.

Illustration courtesy R. Hurt, SSC/Caltech/NASA

Dave Mosher

for National Geographic News

Published July 19, 2012

In a surprise find, astronomers have discovered a planet possibly covered with oceans of magma "right around the corner."

Even more exciting to scientists is its size: about the same as Mars's, which would make the new world the closest known planet smaller than Earth.

Video: NASA Visualization of New Planet UCF-1.01

 

 

Researchers using NASA's Spitzer Space Telescope essentially stumbled upon the new planet while studying a hot, Neptune-size planet called GJ 436b.

In their data, however, the team caught a faint signal of the new planet and named it UCF-1.01, after their institution, the University of Central Florida. Both worlds were detected by watching for regular dimming of their host star, indicating a planet transiting, or crossing in front of, the star.

Thirty-three light years away, "we have a sub-Earth-sized planet that's slightly larger than Mars and essentially right around the corner, at least on a cosmic scale," said Kevin Stevenson, a planetary scientist now at the University of Chicago, who led the study that revealed UCF-1.01.

"It's one of the nearest transiting planets, it's tiny, and it may not be alone."

(Also see "New Planet Found in Our Solar System.")

It's a Small World After All

Large planets are easier to find, but they're generally gas giants that don't have a rocky surface or an atmosphere like Earth's. So scientists are scanning the skies for smaller worlds, which should be more likely to support life as we know it.

NASA's Kepler space observatory, in particular, is actively hunting for Earth-size planets around sunlike stars. In three years it has found more than 3,000 potential new worlds and confirmed dozens (find out how). But Kepler scans parts of the sky between 100 and 2,000 light-years away, giving it a blind spot closer to home.

(Also see "Record Nine-Planet Star System Discovered?")

Spitzer's infrared detectors can "see" planets within a hundred light-years of Earth, but the telescope is normally used to fine-tune our knowledge of farther-out planets that scientists already know about.

"We weren't looking for this planet, even though other researchers suspected it might be there," Stevenson said.

UCF-1.01 is about 5,200 miles (8,400 kilometers) wide, making about a quarter the volume of Earth. And with a year that lasts only 1.4 Earth days, the new planet's orbit takes UCF-1.01 searingly close to its star.

"The only thing separating the planet from the star is about seven times the distance between the Earth and the moon," said Stevenson, who noted the probably lacks an atmosphere.

"It could be a thousand degrees Fahrenheit [540 degrees Celsius]. That may be hot enough to make an ocean of molten rock."

(Related: "New 'Deep Fried' Planets Found-Survivors of Star Death.")

Planetary Companion?

Until the mass of UCF-1.01 is known, the planet can't be confirmed by official standards. "But we know it's there," Stevenson said.

And it may have hidden company. The larger planet, GJ 436b, has an oblong orbit likely caused by the gravitational pull of another planet or planets. And, Stevenson explained, the small planet alone doesn't seem strong enough to explain the eccentric orbit of its big companion.

"At some point I'd like to go back and make new observations," Stevenson said. "There could be a third planet there, called UCF-1.02."

A study of the new planet has been accepted for publication in The Astrophysical Journal.

More: Go behind the search for planets with National Geographic magazine >>

0 comments

Share

Feed the World

  • How to Feed Our Growing Planet

    How to Feed Our Growing Planet

    National Geographic explores how we can feed the growing population without overwhelming the planet in our food series.

See blogs, stories, photos, and news »

Latest Photo Galleries

See more photos »

Shop Our Space Collection

  • Be the First to Own <i>Cosmos: A Spacetime Odyssey</i>

    Be the First to Own Cosmos: A Spacetime Odyssey

    The updated companion book to Carl Sagan's Cosmos, featuring a new forward by Neil deGrasse Tyson is now available. Proceeds support our mission programs, which protect species, habitats, and cultures.

Shop Now »