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Interstellar abundance determinations from fits to X-ray absorption edges often rely on the incorrect assumption that scattering is insignificant and can be ignored. We show instead that scattering contributes significantly to the…

High Energy Astrophysical Phenomena · Physics 2016-02-05 John A. Hoffman , Bruce T. Draine

In the interstellar medium (ISM), the formation of complex organic molecules (COMs) is largely facilitated by surface reactions. However, in cold dark clouds, thermal desorption of COMs is inefficient because of the lack of thermal energy…

Astrophysics of Galaxies · Physics 2022-09-07 Alec Paulive , Joshua T. Carder , Eric Herbst

Grain alignment theory suggests that grains should be aligned in circumstellar regions and the observational data available supports this conclusion. We discuss the alignment of grains via (1) magnetic relaxation, (2) mechanical processes,…

Astrophysics · Physics 2007-05-23 Lazarian A

It is generally agreed that interstellar dust grains consist of two main components, namely, silicates and graphites. Some models, like MRN model, assume these grains to be homogeneous spheres following a power law size distribution. This…

Astrophysics of Galaxies · Physics 2009-03-30 Ashim K. Roy , Subodh K. Sharma , Ranjan Gupta

(abridged) We aim to predict the most important parameters for grain-grain collision outcomes for models of interstellar grain population evolution on astrophysical scales: the threshold velocity above which colliding grains shatter, the…

The interstellar medium is characterised by an intricate filamentary network which exhibits complex structures. These show a variety of different shapes (e.g. junctions, rings, etc.) deviating strongly from the usually assumed cylindrical…

Astrophysics of Galaxies · Physics 2021-07-14 Elena Hoemann , Stefan Heigl , Andreas Burkert

This review provides an introduction to presolar grains - preserved stardust from the interstellar molecular cloud from which our solar system formed - found in primitive meteorites. We describe the search for the presolar components, the…

Astrophysics · Physics 2015-06-24 Katharina Lodders , Sachiko Amari

Since molecules are ubiquitous in space, the study of the 'Molecular Universe' could unfold the mystery of the existing Interstellar medium. Star formation is linked to the chemical evolution processes. Thus, an analysis of the formation of…

Astrophysics of Galaxies · Physics 2024-05-29 Bratati Bhat

The chemical makeup of our solar system is a reflection of Galactic chemical evolution in the local interstellar medium (ISM) over the past ~9 Ga before the formation of the solar system. Although the incorporated ISM dust was mostly…

Solar and Stellar Astrophysics · Physics 2025-02-05 Nan Liu

We introduce a simple theoretical model that describes the interaction of light with optical metamaterials in terms of interfering optical plane waves. In this model, a metamaterial is considered to consist of planar arrays of densely…

Optics · Physics 2013-11-25 P. Grahn , A. Shevchenko , M. Kaivola

Ongoing surveys are in the process of measuring the chemical abundances in large numbers of stars, with the ultimate goal of reconstructing the formation history of the Milky Way using abundances as tracers. However, interpretation of these…

Astrophysics of Galaxies · Physics 2018-10-17 Lucia Armillotta , Mark R. Krumholz , Yusuke Fujimoto

We study the chemical evolution of interstellar grain mantle by varying the physical parameters of the interstellar medium (ISM). To mimic the exact interstellar condition, gas grain interactions via accretion from the gas phase and…

Solar and Stellar Astrophysics · Physics 2011-09-14 Ankan Das , Sandip K. Chakrabarti

We present an experimental system suitable for producing spherical crystals and for observing the distribution of lattice defects (disclinations and dislocations) on a significant fraction (50%) of the sphere. The introduction of…

Soft Condensed Matter · Physics 2007-05-23 Thomas Einert , Peter Lipowsky , Jorg Schilling , Mark J. Bowick , Andreas Bausch

Context. The combination of wideband receivers and spectrometers currently available in (sub-)millimeter observatories deliver wide- field hyperspectral imaging of the interstellar medium. Tens of spectral lines can be observed over degree…

The interstellar medium (ISM) is the material that fills the space between the stars in all galaxies; it is a multi-phase medium in pressure equilibrium, with densities and temperatures covering over 6 orders of magnitude. Although…

Astrophysics of Galaxies · Physics 2025-04-03 Amelie Saintonge

The isothermal gravitational collapse and fragmentation of a molecular cloud region and the subsequent formation of a protostellar cluster is investigated numerically. The clump mass spectrum which forms during the fragmentation phase can…

Astrophysics · Physics 2007-05-23 Ralf Klessen , Andreas Burkert

Semi-empirical molecular dynamics is used to simulate hydrocarbon grain sputtering and collisions which are extremely difficult to study experimentally. This microscopic and dynamic approach is particularly suited to high velocity impacts,…

Astrophysics · Physics 2009-11-10 Reanud Papoular

Presolar grains are stardust particles that condensed in the ejecta or in the outflows of dying stars and can today be extracted from meteorites. They recorded the nucleosynthetic fingerprint of their parent stars and thus serve as valuable…

Solar and Stellar Astrophysics · Physics 2024-12-02 Hung Kwan Fok , Marco Pignatari , Benoît Côté , Reto Trappitsch

Most metallic and ceramic materials are comprised of a space-filling collection of crystalline grains separated by grain boundaries. While this grain structure has been studied for more than a century, there few rigorous results regarding…

Materials Science · Physics 2021-10-29 Erdem Eren , Jeremy Kyle Mason

I present an overview of the hierarchy of structures existing in the interstellar medium (ISM) and the possible mechanisms that cause the fragmentation of one level into the next, with the formation of stars as its last step. Within this…

Astrophysics · Physics 2009-11-10 Enrique Vazquez-Semadeni