1998/01/30 by F. Combes, Combes, F., D. Pfenniger +1
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9801319
8 pages, 2 figures, to be published in Proceedings of Firenze-Arcetri conference, "H2 in the Early Universe", Dec 4-6 1997, ed. E. Corbelli, D. Galli, F. Palla, Mem. S. A. It. Press
arxiv created 1998/01/30 · openalex publication_date 1998/01/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Over the last two decades, realistic studies have often concluded that the first bound objects to form can be very small, much smaller than a solar mass. After recombination, the Jeans mass drops rapidly to the order of a Giant Molecular Cloud (GMC) mass (∼ 105 M_\odot), and the H2 cooling can make the collapse quasi-isothermal; this leads to recursive fragmentation, and formation of clumps so dense that 3-body reactions transform the gas almost entirely to the molecular phase. This could lead to star formation in some places, but since star formation is very inefficient, most of the molecular gas could consist of a fractal built on clumpuscules thermalized with the background radiation, and filling a tiny fraction of the volume. The bulk of the gas mass can therefore be trapped in this phase, well before the first stars re-heat and re-ionize the diffuse gaseous medium. This results in a very contrasted multi-phase baryonic medium, that has partly remained until the present time.