Laboratory Astrophysics

Our understanding of some of the key astrophysical processes in the interstellar medium and circumstellar environments is based on the understanding of the physical and chemical processes that generate and modify dust grains and molecules under different conditions. The knowledge of these processes helps us to understand the spectra, composition, and structure of astronomical objects. Dust and molecules can be observed in nearly all astrophysical environments including evolved stars, star-forming regions, protoplanetary disks, comets, and the surface of planets.

The MPIA runs a laboratory astrophysics facility at the Institute for Solid State Physics of the University of Jena headed by C. Jäger. In this Laboratory Astrophysics and Cluster Physics Group, we study the condensation, processing, and spectral properties of carbonaceous and siliceous dust grains and astrophysically relevant molecules that may play a role as progenitors of grain formation. Laboratory astrophysics is an interdisciplinary field whose research profits from sophisticated experimental facilities.

Molecules, clusters, and nanoparticles are prepared in vacuum chambers under conditions coming close to those in interstellar or circumstellar environments (low pressures and definite temperatures ranges). In our laboratory, we are able to simulate astrophysically relevant processes such as gas phase condensation of grains and molecules at very high (> 1000 K) and very low temperatures (~6 K) by laser-induced pyrolysis of hydrocarbons or laser ablation of solids combined with cryogenic chambers. Sophisticated analytical tools comprising in-situ optical spectroscopy in the UV and IR range, mass spectrometry, chromatography, and electron microscopy help us to characterize the composition and structure of the produced laboratory particulate and molecular analogues.

Spectroscopy in the UV/Vis/IR is the link to astronomical observations. Therefore, a main part of our work is focused on the measurement of the spectral properties of dust grains and molecules in the laboratory. The spectral properties reflect the composition, structure, and temperature of the grains and molecules and have to be measured for every phase in their life-cycle. Spectroscopy from the ultraviolet to the infrared of astrophysically relevant molecules can be performed at low temperatures in free jets and cryogenic rare gas matrices. The spectral properties of gas-phase condensed or processed dust materials can be measured in-situ without exposure to air in a temperature range between 10 and 300 K.

Present projects in our group focus on the UV/Vis/IR spectroscopy of polycyclic aromatic hydrocarbons (PAHs), hydrogenated, and substituted PAHs in free jets and cryogenic rare gas matrices, on the study of simple reactions between silicon, magnesium, oxygen, carbon and small molecules at very low temperature in helium droplets and cosmic ices, on the recondensation of dust at low-temperature and low density in the interstellar medium, on the formation, processing, and stability of silicates, carbon particles, and cosmic ices in different astrophysical environments under UV and X-ray irradiation as well as ion bombardment. For more information on our research we refer to the website of the laboratory astrophysics facility.

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