Thermal instabilities in protogalactic clouds

Details Thermal instabilities in protogalactic clouds Thermal instabilities in protogalactic clouds

Jul 1990

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990nascp3084..267m&link_type=abstract

In NASA, Ames Research Center, The Interstellar Medium in External Galaxies: Summaries of Contributed Papers p 267-268 (SEE N91-

Astronomy and Astrophysics

Astrophysics

Astrophysics, Globular Clusters, Star Formation, Thermal Instability, Augmentation, Collapse, Cooling, Fragments, Hydrodynamics, Ionization, Perturbation, Shock Heating, Slopes, Symmetry

Scientific paper

The means by which a protogalaxy can fragment to form the first generation of stars and globular clusters remains an important problem in astrophysics. Gravitational instabilities grow on timescales too long to drive fragmentation before the background density grows by many orders of magnitude (see Murray and Lin 1989a, and references therein). Thermal instability provides a much more likely mechanism. After its initial collapse, a protogalactic cloud is expected to be shock heated to its virial temperature approx. 106 K. Cooling by H and He+ below 106 K has a negative slope, so that the cloud is subject to strong thermal instabilities. Density enhancements may then grow rapidly, fragmenting the protogalaxy as it cools to lower temperatures. The role of dynamical effects upon the growth of perturbations is considered here. The method used is similar to that used in Murray and Lin (1989a; see also the Erratum to appear September 15), which examined the growth of thermal instabilities with a one-dimensional Lagrangian hydrodynamics code, written for spherical symmetry. Perturbed regions therefore take the form of shells. The dynamical variables are integrated explicitly, while the temperature, ionization fraction, and molecular fraction are integrated implicitly, and account is taken for non-equilibrium values of these quantities.

Affiliated with

Also associated with

No associations

Rating

Thermal instabilities in protogalactic clouds 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 Thermal instabilities in protogalactic clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermal instabilities in protogalactic clouds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1096051