NGC 7538, near the Bubble Nebula, is the largest example of one of these objects discovered, and a rapid increase in accretion in these objects causes FU Orionis variability. The virial theorem is used to derive the Jeans criterion for the formation of these entities, which are formed after turbulent fragmentation of a giant molecular cloud. Hydrostatic constraints cause these objects to follow the Hayashi Track. These entities can undergo mass loss via supersonic jets and form (*) Herbig-Haro objects. It is believed that lithium burning powers their T Tauri variability. When above the Jeans Mass but below 0.072 solar masses, these objects will never progress to the main sequence, instead becoming brown dwarves. For 10 points, name this type of pre main sequence star.
NGC 7538, near the Bubble Nebula, is the largest example of one of these objects discovered, and a rapid increase in accretion in these objects causes FU Orionis variability. The virial theorem is used to derive the Jeans criterion for the formation of these entities, which are formed after turbulent fragmentation of a giant molecular cloud. Hydrostatic constraints cause these objects to follow the Hayashi Track. These entities can undergo mass loss via supersonic jets and form (*) Herbig-Haro objects. It is believed that lithium burning powers their T Tauri variability. When above the Jeans Mass but below 0.072 solar masses, these objects will never progress to the main sequence, instead becoming brown dwarves. For 10 points, name this type of pre main sequence star.
NGC 7538, near the Bubble Nebula, is the largest example of one of these objects discovered, and a rapid increase in accretion in these objects causes FU Orionis variability.
Protostar [prompt on star]