Molecular clouds are collections of gas and dust in space. When left alone,
the clouds remain in their state of peaceful equilibrium.
But when triggered by some external agent, like supernova remnants,
shockwaves can propagate through the gas and dust to create pockets of dense
material. At a certain limit, that dense gas and dust collapses and begins
to form new stars.
Astronomical observations do not have high enough spatial resolution to
observe these processes, and numerical simulations cannot handle the
complexity of the interaction between clouds and supernova remnants.
Therefore, the triggering and formation of new stars in this way remains
mostly shrouded in mystery.
In Matter and Radiation at Extremes, by AIP Publishing in partnership with
China Academy of Engineering Physics, researchers from the Polytechnic
Institute of Paris, the Free University of Berlin, the Joint Institute for
High Temperatures of the Russian Academy of Sciences, the Moscow Engineering
Physics Institute, the French Alternative Energies and Atomic Energy
Commission, the University of Oxford, and Osaka University modeled the
interaction between supernova remnants and molecular clouds using a
high-power laser and a foam ball.
The foam ball represents a dense area within a molecular cloud. The
high-power laser creates a blast wave that propagates through a surrounding
chamber of gas and into the ball, where the team observed the compression
using X-ray images.
"We are really looking at the beginning of the interaction," said author
Bruno Albertazzi. "In this way, you can see if the average density of the
foam increases and if you will begin to form stars more easily."
The mechanisms for triggering star formation are interesting on a number of
scales. They can impact the star formation rate and evolution of a galaxy,
help explain the formation of the most massive stars, and have consequences
in our own solar system.
"Our primitive molecular cloud, where the sun was formed, was probably
triggered by supernova remnants," said author Albertazzi. "This experiment
opens a new and promising path for laboratory astrophysics to understand all
these major points."
While some of the foam compressed, some of it also stretched out. This
changed the average density of the material, so in the future, the authors
will need to account for the stretched mass to truly measure the compressed
material and the shockwave's impact on star formation. They plan to explore
the influence of radiation, magnetic field, and turbulence.
"This first paper was really to demonstrate the possibilities of this new
platform opening a new topic that could be investigated using high-power
lasers," said Albertazzi.
Reference:
B. Albertazzi, P. Mabey, Th. Michel, G. Rigon, J. R. Marquès, S. Pikuz, S.
Ryazantsev, E. Falize, L. Van Box Som, J. Meinecke, N. Ozaki, G. Gregori, M.
Koenig. Triggering star formation: Experimental compression of a foam ball
induced by Taylor–Sedov blast waves. Matter and Radiation at Extremes, 2022; 7
(3): 036902
DOI: 10.1063/5.0068689
Tags:
Space & Astrophysics