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相关论文: Coagulation and Fragmentation in molecular clouds.…

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In dense molecular clouds collisions between dust grains alter the ISM-dust size distribution. We study this process by inserting the results from detailed numerical simulations of two colliding dust aggregates into a coagulation model that…

太阳与恒星天体物理 · 物理学 2015-05-13 C. W. Ormel , D. Paszun , C. Dominik , A. G. G. M. Tielens

In this study, we explore the impact of inhomogeneities in the spatial distribution of interstellar dust on spatial scales of $\le1$ au caused by ion shadowing forces on the optical properties of diffuse interstellar medium (ISM) as well as…

星系天体物理 · 物理学 2020-05-27 Andrei B. Ostrovskii , S. Yu. Parfenov , A. I. Vasyunin , A. V. Ivlev , V. A. Sokolova

We determine the time evolution of the dust particle size distribution during the collapse of a cloud core, accounting for both dust coagulation and dust fragmentation, to investigate the influence of dust growth on non-ideal…

太阳与恒星天体物理 · 物理学 2022-07-20 Yoshihiro Kawasaki , Shunta Koga , Masahiro N. Machida

The size and composition of dust grains are critical in setting the dynamical, physical and chemical evolution of the media in which they are present. Thanks to facilities such as ALMA and in the future the SKA, their thermal emission in…

星系天体物理 · 物理学 2019-11-06 N. Ysard , M. Koehler , I. Jimenez-Serra , A. P. Jones , L. Verstraete

The distances to which the optical flash destroys dust via sublimation, and the burst and afterglow change the size distribution of the dust via fragmentation, are functions of grain size. Furthermore, the sublimation distance is a…

天体物理学 · 物理学 2007-05-23 Daniel E. Reichart

Variations in the observed dust emission and extinction indicate a systematic evolution of grain properties in the transition from the diffuse interstellar medium (ISM) to denser molecular clouds. The differences in the dust spectral energy…

星系天体物理 · 物理学 2015-06-05 Melanie Köhler , Nathalie Ysard , Anthony P. Jones

Dust grains coagulate into larger aggregates in dense gas. This changes their size distribution and possibly affects the thermal evolution of star-forming clouds. We here investigate dust coagulation in collapsing pre-stellar cores with…

星系天体物理 · 物理学 2015-05-13 Hiroyuki Hirashita , Kazuyuki Omukai

Grains are determinant for setting the chemical, physical, dynamical, and radiative properties of all the media in which they are present. Their influence depends on the grain composition, size, and geometrical structure which vary…

星系天体物理 · 物理学 2018-10-03 N. Ysard , A. P. Jones , K. Demyk , T. Boutéraon , M. Koehler

We present high resolution ($1024^3$) simulations of super-/hyper-sonic isothermal hydrodynamic turbulence inside an interstellar molecular cloud (resolving scales of typically 20 -- 100 AU), including a multi-disperse population of dust…

星系天体物理 · 物理学 2018-12-19 Lars Mattsson , Akshay Bhatnagar , Fred A. Gent , Beatriz Villarroel

Models of astrophysical dust are key to understand several physical processes, from the role of dust grains as cooling agents in the ISM to their evolution in dense circumstellar disks, explaining the occurrence of planetary systems around…

星系天体物理 · 物理学 2025-06-18 M. -A. Carpine , N. Ysard , A. Maury , A. Jones

We investigate shattering and coagulation of dust grains in turbulent interstellar medium (ISM). The typical velocity of dust grain as a function of grain size has been calculated for various ISM phases based on a theory of grain dynamics…

天体物理学 · 物理学 2009-11-13 Hiroyuki Hirashita , Huirong Yan

Variations in the grain size distribution are to be expected in the interstellar medium (ISM) due to grain growth and destruction. In this work, we present a dust collision model to be implemented inside a magnetohydrodynamical (MHD) code…

星系天体物理 · 物理学 2021-03-24 L. Beitia-Antero , A. I. Gómez de Castro

Context. Dust grains coagulate to form dust aggregates in protoplanetary disks. Their porosity can be extremely high in the disks. Although disk emission may come from fluffy dust aggregates, the emission has been modeled with compact…

地球与行星天体物理 · 物理学 2014-09-05 Akimasa Kataoka , Satoshi Okuzumi , Hidekazu Tanaka , Hideko Nomura

We report the first uniform and systematic study of dust and molecular gas in nearby molecular clouds. We use surveys of dust extinction and emission to determine the opacity and map the distribution of the dust within a dozen local clouds…

星系天体物理 · 物理学 2022-05-25 John Arban Lewis , Charles J. Lada , Thomas Dame

In this paper we study the effects of inclusions and porosities on the emission properties of silicate grains and compare the model curves with the observed infrared emission from circumstellar dust. We calculate the absorption efficiency…

太阳与恒星天体物理 · 物理学 2015-03-17 D. B. Vaidya , Ranjan Gupta

We argue that impact velocities between dust grains with sizes less than $\sim 0.1$ $\mu m$ in molecular cloud cores are dominated by drift arising from ambipolar diffusion. This effect is due to the size dependence of the dust coupling to…

星系天体物理 · 物理学 2020-09-30 Kedron Silsbee , Alexei Ivlev , Paola Caselli , Olli Sipila , Bo Zhao

We investigated the effect of time-dependent ice growth on dust grains on the opacity and hence on the dust temperature in a collapsing molecular cloud core, with the aim of quantifying the effect of the dust temperature variations on ice…

星系天体物理 · 物理学 2024-10-16 O. Sipilä , P. Caselli , M. Juvela

We have studied the opacity of dust grains at submillimeter wavelengths by estimating the optical depth from imaging at 160, 250, 350, and 500 um from the Herschel Gould Belt Survey and comparing this to a column density obtained from the…

Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\mu$m that…

Dust grains grow in interstellar clouds by accretion and coagulation. In this paper, we focus on these two grain growth processes and numerically investigate how they interplay to increase the grain radii. We show that accretion efficiently…

星系天体物理 · 物理学 2015-06-04 Hiroyuki Hirashita
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