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The cross section of material in debris discs is thought to be dominated by the smallest grains that can still stay in bound orbits despite the repelling action of stellar radiation pressure. Thus the minimum (and typical) grain size…

Solar and Stellar Astrophysics · Physics 2015-10-28 Nicole Pawellek , Alexander V. Krivov

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

We calculate the physical structure of protoplanetary disks by evaluating the gas density and temperature self-consistently and solving separately for the dust temperature. The effect of grain growth is taken into account by assuming a…

Astrophysics · Physics 2009-11-11 Yuri Aikawa , Hideko Nomura

Context. Interstellar ice is the main form of metal species in dark molecular clouds. Experiments and observations have shown that the ice is significantly processed after the freeze-out of molecules onto grains. The processing is caused by…

Astrophysics of Galaxies · Physics 2013-06-14 Juris Kalvāns , Ivar Shmeld

Understanding the evolution of dust and molecular hydrogen (H$_2$) is a critical aspect of galaxy evolution, as they affect star formation and the spectral energy distribution of galaxies. We use the $N$-body/smoothed-particle-hydrodynamics…

Astrophysics of Galaxies · Physics 2022-05-25 Leonard E. C. Romano , Kentaro Nagamine , Hiroyuki Hirashita

We present a multiscale modelling framework that integrates density functional theory (DFT) with a phase-field model (PFM) to explore the intricate dynamics of grain growth in nanocrystalline {\alpha}-Fe single-phase alloy in the presence…

Materials Science · Physics 2024-06-13 Sandip Guin , Albert Linda , Yu-Chieh Lo , Somanth Bhowmick , Rajdip Mukherjee

Aims: We aim to investigate the abundances of light deuterium-bearing species such as HD, H2D+ and D2H+ in a gas-grain chemical model including an extensive description of deuterium and spin state chemistry, in physical conditions…

Astrophysics of Galaxies · Physics 2015-06-15 O. Sipilä , P. Caselli , J. Harju

In the inner regions of protoplanetary discs, ionization chemistry controls the fluid viscosity, and is thus key to understanding various accretion, outflow and planet formation processes. The ionization is driven by thermal and non-thermal…

Earth and Planetary Astrophysics · Physics 2024-11-25 Morgan Williams , Subhanjoy Mohanty

The origin of grain size distribution in the interstellar medium is one of the most fundamental problems in the interstellar physics. In the Milky Way, smaller grains are more abundant in number, but their origins are not necessarily…

Astrophysics of Galaxies · Physics 2015-05-19 Hiroyuki Hirashita

Molecular clouds are the cold regions of the Milky Way where stars form. They are enriched by rather complex molecules. Many of these molecules are believed to be synthesized on the icy surfaces of the interstellar submicron-sized dust…

Astrophysics of Galaxies · Physics 2020-07-08 Stefano Pantaleone , Joan Enrique-Romero , Cecilia Ceccarelli , Piero Ugliengo , Nadia Balucani , Albert Rimola

Context: Chemical models of dense cloud cores often utilize the so-called pseudo-time-dependent approximation, in which the physical conditions are held fixed and uniform as the chemistry occurs. In this approximation, the initial…

Solar and Stellar Astrophysics · Physics 2015-05-18 G. E. Hassel , E. Herbst , E. A. Bergin

We consider the lifecycle of dust introduced into the hot interstellar medium in isolated elliptical galaxies. Dust grains are ejected into galactic-scale cooling flows in large ellipticals by normal mass loss from evolving red giants.…

Astrophysics · Physics 2016-08-30 John C. Tsai , William G. Mathews

We investigated the chemical evolutions of gas phase and grain surface species across the Taurus molecular cloud-1 (TMC-1) filament from translucent phase to dense phase. By comparing observations with modeling results from an up-to-date…

Astrophysics of Galaxies · Physics 2022-04-11 Long-Fei Chen , Di Li , Donghui Quan , Xia Zhang , Qiang Chang , Xiaohu Li , Lin Xiao

Icy grain mantles are the main reservoir of the volatile elements that link chemical processes in dark, interstellar clouds with the formation of planets and composition of their atmospheres. The initial ice composition is set in the cold,…

AIM: We have recently developed a microscopic Monte Carlo approach to study surface chemistry on interstellar grains and the morphology of ice mantles. The method is designed to eliminate the problems inherent in the rate-equation formalism…

Astrophysics · Physics 2009-11-13 Q. Chang , H. M. Cuppen , E. Herbst

Processing by interstellar photons affects the composition of the icy mantles on interstellar grains. The rate of photodissociation in solids differs from that of molecules in the gas phase. The aim of this work was to determine an average,…

Astrophysics of Galaxies · Physics 2018-05-16 Juris Kalvans

We study the impact of dust evolution in a protoplanetary disk around a T Tauri star on the disk chemical composition. For the first time we utilize a comprehensive model of dust evolution which includes growth, fragmentation and…

Astrophysics of Galaxies · Physics 2015-05-20 A. I. Vasyunin , D. S. Wiebe , T. Birnstiel , S. Zhukovska , Th. Henning , C. P. Dullemond

We investigated the chemistry of nitrogen--containing species, principally isotopomers of CN, HCN, and HNC, in a sample of pre-protostellar cores. We used the IRAM 30 m telescope to measure the emission in rotational and hyperfine…

Solar and Stellar Astrophysics · Physics 2015-05-18 Pierre Hily-Blant , Malcolm Walmsley , G. Pineau Des forêts , David Flower

Context: Observations of scattered light in the 1-5 $\mu$m range have revealed dust grains in molecular cores with sizes larger than commonly inferred for the diffuse interstellar medium. It is currently unclear whether these grains are…

Astrophysics of Galaxies · Physics 2014-09-05 M. Andersen , W-F. Thi , J. Steinacker , N. Tothill

Cold cores are an early step of star formation, characterized by densities > 10$^4$ cm$^{-3}$, low temperatures (< 15 K), and very low external UV radiation. We investigate the physico-chemical processes at play to tracing the origin of…

Astrophysics of Galaxies · Physics 2023-01-04 A. Taillard , V. WakelaM , P. Gratier , E. Dartois , M. Chabot , J. A. Noble , J. V. Keane , A. C. A. Boogert , D. Harsono