EPoS Contribution
EPoS Contribution
Revisiting spherical gravitational collapse

Enrique Vazquez-Semadeni
IRyA UNAM, Morelia, MX
I will revisit the hypotheses leading to the classical quasi-static prestellar evolution for dense cores, followed by inside-out collapse during the protostellar stage. These hypotheses appear virtually unrealizable in practice, and the actual prestellar evolution should be closer to the dynamic "early path" solution of Whitworth & Summers. I will then describe a model for the dynamic evolution of the density profile from the onset of collapse to the formation of a protostar, showing that its logarithmic slope approaches a value of -2, and that, for slopes shallower than -2, the radial dependence of the mass accretion rate implies that the core accumulates mass, allowing it to grow. Most observed cores show slopes shallower than -2. Also, there is always an inner part of the core that is locally Jeans stable, and grows by the compression of the outer parts. Similarly, in the magnetic case, there is always an inner part that is always magnetically subcritical, but is compressed by the outer supercritical parts. These results suggest that the observed "transition to coherence" in many cores may be actually the manifestation of the infall speed profile rather than of the dissipation of turbulent support. Synthetic observations support this conclusion.
Caption: Distribution of observed logarithmic slopes of the spherically-averaged density profile for a compilation of low- and high-mass cores.
Collaborators:
G. Gomez
A. Palau
R. Naranjo-Romero
R. Guerrero-Gamboa
R. Loughnane
S. Xu
Y. Hu
Key publication

Suggested Session: Cores