AST 309 Chapter Notes - Chapter 9: Planetary System, Formins, Hr 8799
Document Summary
Unusual discoveries in 2013: a planet found near no star, a gas giant orbiting at an unfathomable distance, and a system containing an orbital plane 45 degrees out of whack. Imagine the early disk environment around a newly born star. The protoplanetary disk contains lots of dust and gas left over from the initial collapse of the interstellar cloud from which the star forms. The star and disk rotate about a common center of gravity, and the rotating debris can evolve in the disk to form planets. There are two widely held theories for how giant gas planets can form: Occurs from the collision and coagulation of solid particles into gradually larger bodies until a massive enough planetary embryo is formed to accrete a gaseous envelope. A massive disk rapidly cools, causing it to fragment into planet- sized, self-gravitating clumps. The primary accepted mechanism is the first theory, core accretion.
