Astronomers discover scaled-down Jupiter and Saturn in a faraway solar system like our own

Over the next few months, Gaudi demonstrated that this two-planet interpretation was correct. Then David Bennett, a research associate professor of astrophysics and cosmology at the University of Notre Dame, refined Gaudi's preliminary model using sophisticated software, and revealed additional details about the system.

This is the third time a Jupiter-mass planet was found by microlensing, Gaudi explained. In the previous two cases, additional planets would have been very difficult to detect, had they been there.

"This is the first time we had a high-enough magnification event where we had significant sensitivity to a second planet -- and we found one." Gaudi said. "You could call it luck, but I think it might just mean that these systems are common throughout our galaxy."

This artist's rendering of a distant solar system shows the location of two newly discovered planets -- one resembling Jupiter (middle right) and one resembling Saturn (bottom). The question mark... Click here for more information.

Astronomers have found two planets at once before, “but using other techniques that don’t pick up on solar systems like ours,” he said.

The newly-discovered planets appear to be gaseous planets like Jupiter and Saturn -- only about 80 percent as big -- and they orbit a star about half the size of the sun. The star is dim and cold compared to ours, issuing only five percent as much light.

Still, the new solar system appears to be a smaller analog of our own. The larger planet is about as massive compared to its star as Jupiter is to ours. The smaller planet shares a similar mass ratio with Saturn.

Also, the smaller planet is roughly twice as far from its star as the larger one, just as Saturn is roughly twice as far away from the sun as Jupiter. Although the star is much dimmer than our sun, temperatures at both planets are likely to be similar to that of Jupiter and Saturn, because they are closer to their star.

“The temperatures are important because these dictate the amount of material that is available for planet formation,” Gaudi said. “Most theorists think that the biggest planet in our solar system formed at Jupiter's location because that is the closest to the sun that ice can form. Saturn is the next biggest because it is in the next location further away, where there is less primordial material available to form planets.”

“Theorists have wondered whether gas giants in other solar systems would form in the same way as ours did. This system seems to answer in the affirmative.”

The fact that astronomers found the planets during the first event that allowed such a detection suggests that these scaled-down versions of our solar system are very common, he added.