Pre-main-sequence Star

Molecular Cloud Core

Phase in the life-cycle of a star from collapse to remnant.

First Hydrostatic Core

Phase in the life-cycle of a star from collapse to remnant.

Second Core (Protostar)

Phase in the life-cycle of a star from collapse to remnant.

Class 0 Protostar

Phase in the life-cycle of a star from collapse to remnant.

Class I Protostar

Phase in the life-cycle of a star from collapse to remnant.

Class II (T Tauri)

Phase in the life-cycle of a star from collapse to remnant.