T-Tauri Star
A T-Tauri star is a young stellar object not quite yet a true star. They are shrinking under gravity and warming up, but are not yet hot enough in their cores to generate the nuclear reactions that define true stars. They are usually surrounded by a disc of gaseous material from which the star formed, and from which planets will one day also be created. T-Tauri stars are highly magnetic, so they have huge star spots, dwarfing the sunspots that speckle the surface of the Sun.