Influence of accretion on the evolution of low-mass stars in the stage of gravitational contraction

Results are presented for a numerical study of the evolution of a star that has an initial mass of 0.05 solar mass, accretes protocluster cloud material at the rate of 10 to the -7th solar mass/yr during the gravitational contraction stage, and completes its evolution with a final mass of either 0.5 or one solar mass. The study shows that, owing to the effects of accretion on the internal structure of a star during gravitational contraction, stars with a mass of 0.5 or one solar mass may lie below the main sequence by 1-1.5 mag or by 0.25 mag, respectively. It is suggested that the presence of late-type stars below the main sequence in HR diagrams of young clusters may be explained in terms of accretion of protocluster cloud material during the gravitational contraction stage.