On the Stability of Radiation Pressure Dominated Cavities in the Formation of Massive Stars

Details On the Stability of Radiation Pressure Dominated Cavities in the Formation of Massive Stars On the Stability of Radiation Pressure Dominated Cavities in the Formation of Massive Stars

Jan 2012

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012aas...21920805k&link_type=abstract

American Astronomical Society, AAS Meeting #219, #208.05

Astronomy and Astrophysics

Astronomy

Scientific paper

Context: Once massive stars exert a radiation pressure onto their environment higher than gravitational attraction, they launch a radiation pressure driven outflow, which creates cleared polar cavities. Where as such cavities would shield further accretion onto the star from the direction of the bubble, it has been claimed that a radiative Rayleigh-Taylor instability would lead to the collapse of the outflow cavity.
Aims: We investigate the stability of radiation pressure dominated cavities, focusing on its dependence on the radiation transport approach used in numerical simulations.
Methods: We compare two different methods for stellar radiation feedback: gray Flux-Limited Diffusion (FLD) and frequency-dependent Ray-Tracing (RT). Both methods are implemented in our self-gravity radiation-hydrodynamics simulations for various initial density structures of the collapsing clouds. We also derive simple analytical models to support our findings.
Results: Both methods lead to the launch of a radiation pressure dominated outflow cavity. But only FLD cases lead to prominent instability in the cavity shell. The RT cases do not show such instability; once the outflow started, it precedes continuously. The FLD cases display extended epochs of marginal Eddington equilibrium in the cavity shell, making them prone to the radiative Rayleigh-Taylor instability. In the RT cases, the radiation pressure exceeds gravity by 1-2 orders of magnitude. Then the radiative Rayleigh-Taylor instability is consequently suppressed. It is a fundamental property of the gray FLD method to neglect the stellar radiation temperature at the location of absorption and thus to underestimate opacity at the location of the cavity shell.
Conclusions: Treating the stellar irradiation in the gray FLD approximation underestimates the radiative forces acting on the cavity shell. This can artificially lead to situations unstable to the radiative Rayleigh-Taylor instability. The proper treatment of direct stellar irradiation by massive stars is crucial for the stability of radiation pressure dominated cavities.

Affiliated with

Also associated with

No associations

Rating

On the Stability of Radiation Pressure Dominated Cavities in the Formation of Massive Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with On the Stability of Radiation Pressure Dominated Cavities in the Formation of Massive Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Stability of Radiation Pressure Dominated Cavities in the Formation of Massive Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1577628