case western reserve university



The Initial Mass Function of the First Stars

Jennifer Johnson (The Ohio State University)

Stars formed in the early Universe under very different conditions than they do today. Current theoretical models strongly favor an initial mass function peaked toward high mass stars, a prediction that affects reionization, the number of high-redshift supernovae, and the pollution of the primordial interstellar gas. Observing the Galaxy as it was 13 billion years ago is an interesting challenge, and there are several indirect methods of getting information on stars, even those that have long since died. I will review our observational evidence about the IMF of the first stars, focusing on supernova yields for high-mass stars, asymptotic giant branch mass transfer events for intermediate-mass stars, and the metallicity distribution function of halo stars for low-mass stars. These results support the lack of low-mass star formation, but argue against the formation of large numbers of stars with masses greater than 100 solar masses.