Our Solar System Has a Sister 10 Light Years Away
published during a waxing gibbous moon.
05/04/2017

Even though most humans would agree that Earth is special, the Kepler telescope has discovered thousands of potentially habitable planets, some of which may not be so different from ours. Now, SOFIA (Stratospheric Observatory for Infrared Astronomy), NASA’s 747 with a powerful telescope, has found an entire solar system just over 10 light years away that looks a lot like ours.

In early 2015, SOFIA was headed back to its home base in Palmdale, California when pilots focused its telescope on a star called Epsilon Eridani. Eps Eri, as it’s affectionately known, resembles our sun, only it’s significantly younger. Scientists have long thought this system to be similar to our own, which is why it’s often the focus of studies—and probably why creators of the sci-fi show Babylon 5 chose it as the location for its eponymous station.

Scientists already know about Eps Eri’s debris disk, the cosmic material—usually gas, dust, rocks, and ice—that continues to orbit the sun after planets form. Our solar system has two regions that fit this description, the first being the asteroid belt between Mars and Jupiter and the second being the Kuiper belt that extends beyond Neptune. Previous studies also indicated the existence of a Jovian planet orbiting Eps Eri at approximately the same distance as Jupiter is from the sun.
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Eridani /solar system comparison image. Credit: NASA/JPL/Caltech/R. Hurt

A research team at the University of Arizona recently published a study in which it used the images SOFIA obtained in 2015 and data acquired by NASA’s Spitzer telescope to devise models of the Eps Eri system, particularly with regards to the location and formation of the debris disk material. One of the models suggests that the debris exists in two thin rings, one of which is located in a position similar to the solar system’s asteroid belt and the other in a position similar to Uranus’s orbit. Based on this model, the team tentatively theorized that the location of such debris might be related to a planetary system’s largest planet—in other words, perhaps it’s not random that the solar system’s asteroid belt formed near Jupiter. The same thing may have happened in the Eps Eri system and in others.

The second model suggests that the debris might come from a far-off zone like our Kuiper Belt, perhaps even beginning as dust that spreads toward the star, forming a broader disk as opposed to a narrow ring or belt.

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Artist’s conception of Eridani system. Credit: NASA

Based on its studies, as well as the extensive data collected by SOFIA’s FORCAST camera, the research team has determined the accuracy of the first scenario. They believe the system’s debris concentrates around its largest, Jupiter-like planet, and that a planet like Neptune blocks dust from the far reaches of the system. “It really is impressive how Eps Eri, a much younger version of our solar system, is put together like ours,” says lead researcher Kate Su.

 

The similarity of the Epsilon Eridani system to our solar system sheds light on how our planetary system formed and what forces acted upon it long before we were around to observe. Continued examination of the Eps Eri system could help us learn more about how the moon and Mars got their craters, or how Earth’s oceans formed. Eps Eri might be the closest thing researchers have to a time machine that allows them to study the solar system’s past.