Disk Accretion and the Stellar Birthline

摘要

We present a simplified analysis of some effects of disk accretion on the early evolution of fully convective, low-mass premain-sequence stars. Our analysis builds on the previous seminal work of Stahler, but it differs in that the accretion of material occurs over a small area of the stellar surface, such as through a disk or magnetospheric accretion column, so that most of the stellar pho- tosphere is free to radiate to space. This boundary condition is similar to the limiting case consi- dered by Palla & Stahler for intermediate-mass stars. We argue that for a wide variety of disk mass accretion rates, material will be added to the star with relatively small amounts of thermal energy.