Researchers studying the star system Kepler-30, which is 10,000 light-years from Earth, found that its three known worlds all orbit in the same plane, lined up with the rotation of the star — just like the planets in our own solar system.
Cristina Sanchis Ojeda
Astronomers have discovered an alien solar system whose planets are arranged much like those in our own solar system, a find that suggests most planetary systems start out looking the same, scientists say.
Researchers studying the star system Kepler-30, which is 10,000 light-years from Earth, found that its three known worlds all orbit in the same plane, lined up with the rotation of the star — just like the planets in our own solar system do. The result supports the leading theory of planet formation, which posits that planets take shape from a disk of dust and gas that spins around newborn stars.
"In agreement with the theory, we have found the star's spin to be aligned with the planets," said study co-author Dan Fabrycky, of the University of California, Santa Cruz. "So this result is profound because it is basic data testing the standard planet formation theory."
Interactions among planets can later throw such ordered arrangements out of whack, researchers added, creating the skewed orbits seen in many alien systems today. [Gallery: The Strangest Alien Planets]
The Kepler-30 system consists of three known extrasolar planets circling a sunlike star. All three worlds — Kepler-30b, Kepler-30c and Kepler-30d — are much larger than Earth, with two being even more massive than Jupiter.
The three planets were detected in January by NASA's Kepler space telescope, which has spotted more than 2,300 potential alien worlds since its March 2009 launch. Kepler uses the "transit method," noting the telltale brightness dips caused when a planet crosses, or transits, a star's face from the telescope's perspective.