| Title: | Radiation-MHD models of elephant trunks and globules in H II regions
|
| Authors: | Jonathan Mackey and Andrew J. Lim, 2011 |
| Abstract: | We study the formation and evolution of pillars of dense gas, known as
elephant trunks, at the boundaries of H II regions, formed by shadowing
of ionising radiation by dense clumps. The effects of magnetic fields on
this process are investigated using 3D radiation-magnetohydrodynamics
simulations. For a simulation in which an initially uniform magnetic
field of strength |B|≈ 50 micro-G is oriented perpendicular to the
radiation propagation direction, the field is swept into alignment with
the pillar during its dynamical evolution, in agreement with
observations of the “Pillars of Creation” in M16, and of some cometary
globules. This effect is significantly enhanced when the simulation is
re-run with a weaker field of ≈ 18 micro-G. A stronger field with |B| ≈
160 micro-G is sufficient to prevent this evolution completely, also
significantly affecting the photoionisation process. Using a larger
simulation domain it is seen that the pillar formation models studied in
Mackey & Lim (2010) ultimately evolve to cometary structures in the
absence of dense gas further from the star. |
| ICHEC Project: | Numerical Studies of the Evolution of Structures in H II Regions. |
| Publication: | Bulletin de la Société Royale des Sciences de Liège, 2011, Volume 80, pp. 391-395. |
| URL: | http://popups.ulg.ac.be/SRSL/document.php?id=2862 |
| Status: | Published |
