Fig10_7 Evolutionary tracks of protostars

Fig10_7 Evolutionary tracks of protostars

Fig. 10.7 . Evolutionary tracks of protostars of various masses in the Hertzsprung-Russell diagram, ending with their arrival on the main sequence when stars have begun burning hydrogen in their core. The absolute luminosity, L, is given in units of the Sunís absolute luminosity, denoted L?. The star mass is given in units of the Sunís mass, designated M?. The mass values are specified along the main sequence, from upper left to lower right. High-mass stars, which have greater luminosity than low-mass stars, are found at higher points on the main sequence and take a shorter time to arrive there. The protostar lifetimes are given above the relevant track. During star formation, transportation of a protostarís internal energy is dominated by either radiation (horizontal lines) or by convection (vertical lines). Stars with lower mass end up having larger convective zones inside.

Copyright 2010, Professor Kenneth R. Lang, Tufts University