A star acquires much of its mass by accreting material from a disc. Accretion
is probably not continuous but episodic. We have developed a method to include
the effects of episodic accretion in simulations of star formation. Episodic
accretion results in bursts of radiative feedback, during which a protostar is
very luminous, and its surrounding disc is heated and stabilised. These bursts
typically last only a few hundred years. In contrast, the lulls between bursts
may last a few thousand years; during these lulls the luminosity of the
protostar is very low, and its disc cools and fragments. Thus, episodic
accretion enables the formation of low-mass stars, brown dwarfs and
planetary-mass objects by disc fragmentation. If episodic accretion is a common
phenomenon among young protostars, then the frequency and duration of accretion
bursts may be critical in determining the low-mass end of the stellar initial
mass function.Comment: To appear in the Astrophysical Journal. Press release available at:
http://www.astro.cf.ac.uk/pub/Dimitrios.Stamatellos/News/News.html Full
resolution paper available at http://stacks.iop.org/0004-637X/730/3
