NASA's new planet-hunting telescope has found two mystery objects that are too hot to be planets and too small to be stars.
The Kepler space telescope, launched in March, discovered the two new heavenly bodies, each circling its own star. Telescope chief scientist Bill Borucki for NASA said the objects are thousands of degrees hotter than the stars they circle. That means they probably aren't planets. They are bigger and hotter than planets in our solar system, including dwarf planets.
"The universe keeps making strange things stranger than we can think of in our imagination," said Jon Morse, head of astrophysics for NASA.
The new discoveries don't quite fit into any definition of known astronomical objects, and so far don't have a classification of their own. Details about the mystery objects were presented Monday at a meeting of the American Astronomical Society in Washington, D.C.
For now, NASA researcher Jason Rowe, who found the objects, said he calls them "hot companions."
How hot? Try 14,400 C. That's hot enough to melt lead or iron.
There are two leading theories for what the objects might be and those theories cover both ends of the cosmic life cycle:
- Rowe suggests they are newly born planets. New planets have extremely high temperatures, and in this case Rowe speculates they might be only about 200 million years old.
- Ronald Gilliland of the Space Telescope Science Institute says they could be white dwarf stars that are dying and stripping off their outer shells and shrinking.
The primary focus of the Kepler telescope's three-year mission is to find out how common other planets — especially Earth-like planets — are in the universe. To do that, it is scanning a small chunk of the sky, about one 400th of the night sky with more than 150,000 stars to look for planets.
The telescope in just six weeks found its first five confirmed planets, slightly more than astronomers expected from such a quick search. There are hundreds of other candidates that need confirmation.
The five planets are all much larger than Earth, much closer to their stars than Earth is to the sun, and way too hot for life, Borucki said. A couple of these planets are close to 1,649 C.
"Looking at them is like looking at a blast furnace," Borucki said. "Certainly, no place to look for life."
One of the newly discovered planets is so airy that "it has the density of Styrofoam," Borucki said.
"There's going to be all kinds of weird stuff out there," said Alan Boss of the Carnegie Institute of Washington, who wasn't part of the research. "This is an unparalleled data set. The universe really is a weird place. It's fantastic."