Posted on behalf of Ashley Yeager
Astronomers have discovered two asteroid belts in the closest known planetary system to Earth. This could therefore be the ideal place to search for an Earth-like planet and could also offer hints about the early life of our solar system, they say.
Epsilon Eridani, the star at the center of this neighboring system, is slightly cooler and smaller than the sun and is located about 10.5 light-years from Earth. The star is also younger than the sun, with an approximate age of 850 million years.
Astronomers knew a planet of about 60% the mass of Jupiter orbited Epsilon Eridani once every 7 years and that a far-out ring of icy material, much like the Kuiper belt of our solar system, was also present. Now astronomers have detected two other rocky asteroid belts.
The innermost belt actually resembles the asteroid belt in our solar system and sits just three astronomical units (1 AU is the Earth-Sun distance) away from the star. Just beyond it sits the star’s known planet. The second belt sits 20 AUs from Epsilon Eridani. This belt holds 20 times more material than the inner ring and is roughly the same mass as the Moon. The far-out icy ring sits between 35 and 90 AU from Epsilon Eridani.
The presence of three gap-spaced rings implies that unseen planets like Earth confine and shape the debris disks, a team of astronomers will report in a forthcoming issue of The Astrophysical Journal. Spitzer Space Telescope data showed the gaps between each of the three rings.
“Planets are the easiest way to explain what we’re seeing,” says study author Massimo Marengo of the Harvard-Smithsonian Center for Astrophysics, because they could mold the rings gravitationally, just like the moons of Saturn mold that planet’s rings (press release).
The Epsilon Eridani system also “probably looks a lot like ours did when life first took root on Earth”, says Dana Backman of the SETI Institute and the paper’s lead author. Studying it, says Marengo, is therefore “like having a time machine to look at our solar system when it was young”.
News coverage
USA Today points out that Epsilon Eridani “was borrowed by the creators of the TV series Star Trek as the location of Vulcan, the planet that gave us the super-logical science officer Mr. Spock”.
Evidence found of solar system around nearby star – McClatchy Newspapers
Nearest planetary system boasts two asteroid belts – New Scientist
Headline watch
Double the rubble: Nearby star system has two asteroid belts – Science News
Image: artists impression of the system / NASA/JPL-Caltech