Astronomers track the birth of a 'super-Earth'

A new model giving rise to young planetary systems offers a fresh solution to a puzzle that has vexed astronomers ever since new detection technologies and planet-hunting missions such as NASA's Kepler space telescope have revealed thousands of planets orbiting other stars: While the majority of these exoplanets fall into a category called super-Earths—bodies with a mass somewhere between Earth and Neptune—most of the features observed in nascent planetary systems were thought to req