On the formation of stars from disk accretion

Models of stars which form by accretion from a disk have been constructed. Accretion and pre-main-sequence tracks have been calculated for a range of initial parameters which spans the physically reasonable modes for accretion. It is found that the models agree with the observed positions of T Tauri stars in the H-R diagram and avoid some of the problems which are endemic to traditional pre-main-sequence evolution. No evidence is found to indicate that the formation of high- and low-mass stars in young open clusters is noncoeval. A problem is pointed out that arises when attempting to use an H-R diagram of T Tauri stars to distinguish between various models of star formation.