Star Formation, Stellar Feedback, and the Ecology of Galaxies

Giant Herbig-Haro jets have parsec-scale dimensions and thus provide a fossil record of the accretion history of their sources. The
morphology of these major outflows is well explained as the result of a newborn triple system that breaks up, leading to an eccentric binary that spirals in, with accretion and outflow events at each
increasingly close periastron passage. The end result is likely a
spectroscopic binary, but if enough dissipation occurs, the binary
components may merge in a major explosion. I will present evidence for the first such case of a merger event in young low mass stars and discuss the properties of the peculiar star that has resulted. The dynamical interactions that lead to such events play a major role in determining the final masses of the stars involved. Given the ubiquity of young multiple stars, this supports the idea that such processes have an important impact on the shape of the IMF.