Stars seem to have a size limit of 100–150 times that of the Sun; the reason for this has been the subject of debate. Some astronomers think that a large star's own radiation blows away the gas it needs to grow, whereas others suggest that a star's progenitor cloud fragments.

A new simulation bolsters the fragmentation theory. Thomas Peters at the University of Heidelberg in Germany and his colleagues simulated the birth of massive stars in a cloud of gas and found that other, smaller stars formed from the fragmenting gas before the largest one could grow too big. The simulations are supported by some observations, and should lead to a better understanding of how big stars form.

Astrophys. J. 725, 134–145 (2010)