EPoS Contribution
EPoS Contribution
The Feedback Effects of Protostellar Outflows on High Mass and Low Mass Star Formation

Richard I. Klein
University of California, Berkeley and Lawrence Livermore National Laboratory
The formation of massive stars remains one of the most significant unsolved problems in astrophysics, with implications for the production of heavy elements in the universe and the structure and evolution of galaxies. High mass star formation poses a major theoretical challenge: How is it possible to sustain a sufficiently high mass accretion rate into a protostellar core despite the radiation pressure and the dynamical effects of protostellar outflows on the accreting envelope. I present a series of our recent high resolution radiation-hydrodynamic adaptive mesh refinement simulations including for the first time the feedback effects of protostellar outflows on the formation of massive stars by comparing the effects of protostellar outflow feedback with our earlier work that did not include outflows. I show that feedback from protostellar outflows creates highly evacuated optically thin cavities in the surrounding core, drives Kelvin Helmholtz instabilities in the core and allows the efficient escape of radiation through the development of an anisotropic radiation field. I show that with the additional mechanism of protostellar outflows, radiation pressure again cannot halt accretion thereby allowing massive stars to form. I present predictions for massive star formation including outflows with upcoming ALMA submillimeter observations. Finally, with high resolution radiation-hydrodynamic AMR simulations I discuss the effects of protostellar outflow feedback on low mass star formation in a turbulent molecular cloud. I compare the distribution of stellar masses, accretion rates, multiplicity and temperatures in simulations with and without protostellar outflow feedback.
Caption: Three dimensional high mass star formation AMR simulations with protostellar outflows showing a side-on cross cut view of the density in the left panel, a face-on cross cut view of the density in the center panel and the ratio of radiation to gravitational force with arrows indicating the net force relative to the local gravitational force in the right panel. The panels from top to bottom show the massive stellar system at times 26.3, 40, 49.5 and 63.6 kiloyears. After the onset of gravitational instability in the disk at 40 kiloyears, a massive binary system forms with mass of 26.7, 39.0 and 50.1 solar masses. The white dots are stars with < 0.5 solar masses and the crosses are stars with > 0.5 solar masses. At the end of the simulation, the entire 100 solar mass core has collapsed into the circumbinary disk. Interacting protostellar outflows drive Kelvin Helmholtz instabilities in the core.
Collaborators:
A.J. Cunningham, LLNL, USA
C.F. McKee, UC Berkeley, USA
C. Hansen, UC Berkeley, USA
M.R. Krumholz, UCSC, USA
S.S.R. Offner, CFA, USA
Key publication

Suggested Session: Massive Stars, Cores and Collapse