EPoS Contribution
EPoS Contribution
Multi-Physics of Feedback in Massive Star Formation

Rolf Kuiper
U Tübingen, Tübingen, DE
Stars are born within gas mass reservoirs, which collapse under their own gravity. Especially in the case of massive (proto)stars, a variety of feedback effects are opposing gravity and impact the natal environment of the forming star. We have performed simulations of the collapse of pre-stellar mass reservoirs including the feedback effects of thermal pressure, centrifugal forces, protostellar outflows, thermal radiation pressure, stellar radiation pressure, and ionization, i.e. high thermal pressure due to the formation of an HII region. In more than 30 individual core collapse simulations, we determine the importance of each of the individual feedback effects as well as their interplay, by including and excluding their contributions in the equations solved. The newly developed ionization solver makes use of a hybrid scheme for radiation transport and takes into account direct ionization by the UV spectrum of the protostar as well as diffuse UV from direct recombination into the ground state. Further numerical highlights of this study include sub-AU resolution around the forming protostar, the use of frequency-dependent ray-tracing for the stellar radiative feedback, and following the collapse over up to ten free-fall times in each of the simulations, covering the whole accretion phase of the protostar up to disk disruption. After stellar accretion has ceased, we quantify the efficiency of the individual feedback components in terms of the final mass of the star and the mass loss of the initial mass reservoir (see right panel of figure for an example data set). We find ionization feedback plays a role as important as radiative forces. Although initially the HII region is limited to the bipolar low-density cavity of the protostellar outflow, it increases the opening angle with time (see left panel of figure). Moreover, the experiments are performed for two different initial conditions representing different star formation scenarios with either a limited 100 Msol mass reservoir corresponding to an isolated pre-stellar core or with a (virtually unlimited) 1000 Msol large-scale mass reservoir corresponding to a globally collapsing region fed by filaments.
D. Meyer, U Tübingen, DE
D. Kee, U Tübingen, DE
A. Kölligan, U Tübingen, DE
H. Yorke, JPL, USA
N. Turner,JPL, USA
T. Hosokawa, U Tokyo, Japan
R. Pudritz, McMaster, CA
M. Klassen, McMaster, CA
H. Beuther, MPIA, DE
A. Sanna, MPIfR, DE
K. Johnston, U Leeds, GB
Key publication

Suggested Session: Massive Star Formation