A Solar System Like Ours

Astronomers announced Wednesday the discovery of the first solar system other than our own where multiple planets travel around a star in circular orbits.

Of the roughly 70 planets found so far outside our solar system, most travel in tight, erratic orbits around their stars.

However, the two planets around the star 47 Ursae Majoris both travel in nearly circular orbits at a distance that, in our solar system, would place them beyond Mars but within the orbit of Jupiter.

University of California, Berkeley, astronomers announced the discovery of the second planet on Wednesday. The first was detected in 1996.

"With 47 Ursae Majoris, it's heartwarming to find a planetary system that finally reminds us of our solar system," said team member Geoffrey Marcy, a Berkeley professor of astronomy.

The two planets — one 2½ times the size of Jupiter, the other three-quarters as large — orbit a star in the Big Dipper, or Ursa Major, constellation. The star is about 51 light-years from Earth.

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