The Birth of Stars and the Discovery of Planets outside the Solar System (Astronomy)

Recall cards on how stars are born and how we find planets around other stars. Star formation in giant molecular clouds: their cold, filamentary interiors, the dense clumps and cores that collapse, and the vivid example of the Orion molecular cloud and its nebula. The stages of a forming star: protostars, whirling protostellar disks, T Tauri stars, stellar winds, and the jets that light up Herbig-Haro objects. Reading stellar evolution off the H-R diagram: evolutionary tracks, the 12-million-K threshold for reaching the main sequence, and the mass limits of true stars. Evidence that planets form in circumstellar disks, growing by accretion from dust grains to planetesimals to giant planets. And the exoplanet revolution: 51 Pegasi b, the radial-velocity and transit methods, direct imaging, Kepler's harvest, super-Earths and mini-Neptunes, and planetary migration.