New observations from NASA's Spitzer Space Telescope indicate that the nearest planetary system to our own has two asteroid belts. Our own solar system has just one.
The star at the center of the nearby system, called Epsilon Eridani, is a younger, slightly cooler and fainter version of the sun. Previously, astronomers had uncovered evidence for two possible planets in the system, and for a broad, outer ring of icy comets similar to our own Kuiper Belt.
Now, Spitzer has discovered that the system also has dual asteroid belts. One sits at approximately the same position as the one in our solar system. The second, denser belt, most likely also populated by asteroids, lies between the first belt and the comet ring. The presence of the asteroid belts implies additional planets in the Epsilon Eridani system.
"This system probably looks a lot like ours did when life first took root on Earth," said Dana Backman, an astronomer at the SETI Institute, in Mountain View, Calif., and outreach director for NASA's Sofia mission. "The main difference we know of so far is that it has an additional ring of leftover planet construction material." Backman is lead author of a paper about the findings to appear Jan. 10 in the Astrophysical Journal.