Interstellar silicate analogs for grain-surface reaction experiments: Gas-phase condensation and characterization of the silicate dust grains

T. Sabri, L. Gavilan, C. Jäger, J. L. Lemaire, G. Vidali, H. Mutschke, T. Henning

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Amorphous, astrophysically relevant silicates were prepared by laser ablation of siliceous targets and subsequent quenching of the evaporated atoms and clusters in a helium/oxygen gas atmosphere. The described gas-phase condensation method can be used to synthesize homogeneous and astrophysically relevant silicates with different compositions ranging from nonstoichiometric magnesium iron silicates to pyroxene- and olivine-type stoichiometry. Analytical tools have been used to characterize the morphology, composition, and spectral properties of the condensates. The nanometer-sized silicate condensates represent a new family of cosmic dust analogs that can generally be used for laboratory studies of cosmic processes related to condensation, processing, and destruction of cosmic dust in different astrophysical environments. The well-characterized silicates comprising amorphous Mg2SiO4 and Fe 2SiO4, as well as the corresponding crystalline silicates forsterite and fayalite, produced by thermal annealing of the amorphous condensates, have been used as real grain surfaces for H2 formation experiments. A specifically developed ultra-high vacuum apparatus has been used for the investigation of molecule formation experiments. The results of these molecular formation experiments on differently structured Mg2SiO4 and Fe2SiO4 described in this paper will be the topic of the next paper of this series.

Original languageEnglish (US)
Article number180
JournalAstrophysical Journal
Volume780
Issue number2
DOIs
StatePublished - Jan 10 2014

Keywords

  • ISM: molecules
  • astrochemistry
  • dust, extinction
  • molecular processes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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