AstroTalk Episode July 13, 2017

Astronomers Track the Birth of a Super-Earth

3:00pm - 3:30pm

Researchers at Arizona's Steward Observatory and at the Los Alamos National Laboratory in Los Alamos, New Mexico, are tracking the formation of a super-Earth, an exoplanet anywhere from the mass of the Earth, to the mass of Neptune (~ 14 Earth masses). The features of this exoplanet, and of other similar-sized exoplanets, did not match the model for most of the exoplanetsfound in the Milky Way. The features observed with this exo-planet were thought to require more massive planets, in the size range of Jupiter, or even bigger. These astronomers were observing a super-Earth carving out a disk in the gas that surrounds its Sun, in a scenario similar to how the rings in Saturn are carved out. Previous models assumed this could only occur with Jupiter-sized exoplanets. This particular exoplanet was in a much younger stage of its formation, different than many of the other older exoplanets in our Solar System, which orbit stars that are billions of years old. When astronomers previously studied these senior citizens of our galaxy, they had no way of knowing how these planets were born. In studying this particular super-Earth, these scientists are now getting a first-hand look at the younger stages of star and planet formation. In essence, they are getting the chance to study a younger proto-planetary disk, in the younger, or "baby" stages of its formation. Seeing an actual planet forming in a proto-planetary disk is not such an easy thing to do, so the scientists are relying on being able to see the gaps and tracks these planet make as they travel through the gas and dust that surrounds the proto-star. The gaps and their relative positions are posing questions, as scientists try to reconcile their previous models from what they are now seeing.