Star Formation in High Pressure, High Energy Density Environments: Laboratory Experiments of ISM Dust Analogs

Journal Article · Wed Jan 05 00:00:00 EST 2005 · The Dusty and Molecular Universe: A Prelude to Herschel and ALMA

OSTI ID:15015955

van Breugel, W; Bajt, S; Bradley, J; Bringa, E; Dai, Z; Felter, T; Graham, G; Kucheyev, S; Torres, D; Tielens, A; Baragiola, R; Dukes, C; Loeffler, M

Dust grains control the chemistry and cooling, and thus the gravitational collapse of interstellar clouds. Energetic particles, shocks and ionizing radiation can have a profound influence on the structure, lifetime and chemical reactivity of the dust, and therefore on the star formation efficiency. This would be especially important in forming galaxies, which exhibit powerful starburst (supernovae) and AGN (active galactic nucleus) activity. How dust properties are affected in such environments may be crucial for a proper understanding of galaxy formation and evolution. The authors present the results of experiments at LLNL which show that irradiation of the interstellar medium (ISM) dust analog forsterite (Mg{sub 2}SiO{sub 4}) with swift heavy ions (10 MeV Xe) and a large electronic energy deposition amorphizes its crystalline structure, without changing its chemical composition. From the data they predict that silicate grains in the ISM, even in dense and cold giant molecular clouds, can be amorphized by heavy cosmic rays (CR's). This might provide an explanation for the observed absence of crystalline dust in the ISM clouds of the Milky Way galaxy. This processing of dust by CR's would be even more important in forming galaxies and galaxies with active black holes.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15015955
• Report Number(s): UCRL-JRNL-209106; TRN: US0501690
• Journal Information: The Dusty and Molecular Universe: A Prelude to Herschel and ALMA, Other Information: Publication date October 27, 2004; PDF-FILE: 4 ; SIZE: 83.9 KBYTES; PBD: 5 Jan 2005
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
BLACK HOLES
CHEMICAL COMPOSITION
CHEMISTRY
CLOUDS
DUSTS
EFFICIENCY
ENERGY DENSITY
GALAXIES
GRAVITATIONAL COLLAPSE
HEAVY IONS
IONIZING RADIATIONS
IRRADIATION
LIFETIME
MILKY WAY
SILICATES
STARS
SUPERNOVAE