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We investigate the clustering and dynamics of nano-sized particles (nano-dust) in high-resolution ($1024^3$) simulations of compressible isothermal hydrodynamic turbulence. It is well-established that large grains will decouple from a…

星系天体物理 · 物理学 2020-01-08 Lars Mattsson , Johan. P. U. Fynbo , Beatriz. Villarroel

In the standard picture of isolated star formation, dense ``starless'' cores are formed out of magnetic molecular clouds due to ambipolar diffusion. Under the simplest spherical geometry, I demonstrate that ``starless'' cores formed this…

天体物理学 · 物理学 2009-10-31 Zhi-Yun Li

A necessary first step for dust removal in protoplanetary disc winds is the delivery of dust from the disc to the wind. In the case of ionized winds, the disc and wind are sharply delineated by a narrow ionization front where the gas…

地球与行星天体物理 · 物理学 2021-01-20 Richard A. Booth , Cathie J. Clarke

Context. The largest grains (0.5-1 micron) in the interstellar size distribution are efficient in scattering near- and mid-infrared radiation. These wavelengths are therefore particularly well suited to probe the still uncertain high-end of…

星系天体物理 · 物理学 2015-06-17 M. Andersen , J. Steinacker , W-F. Thi , L. Pagani , A. Bacmann , R. Paladini

Shattering of dust grains in the interstellar medium is a viable mechanism of small grain production in galaxies. We examine the robustness or uncertainty in the theoretical predictions of shattering. We identify $P_1$ (the critical…

星系天体物理 · 物理学 2015-06-15 Hiroyuki Hirashita , Hiroshi Kobayashi

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

Millimeter interferometry provides evidence for the presence of mm to cm size "pebbles" in the outer parts of disks around pre-main-sequence stars. The observations suggest that large grains are produced relatively early in disk evolution…

天体物理学 · 物理学 2009-11-13 F. Brauer , C. P. Dullemond , A. Johansen , Th. Henning , H. Klahr , A. Natta

Dust constitutes only about one percent of the mass of circumstellar disks, yet it is of crucial importance for the modeling of planet formation, disk chemistry, radiative transfer and observations. The initial growth of dust from…

地球与行星天体物理 · 物理学 2011-07-19 T. Birnstiel

In a low-metallicity gas, rapid cooling by dust thermal emission is considered to induce cloud fragmentation and play a vital role in the formation of low-mass stars (<~ 1 M_sun) in metal-poor environments. We investigate how the growth of…

星系天体物理 · 物理学 2013-02-13 Gen Chiaki , Takaya Nozawa , Naoki Yoshida

We review the properties of dust in protoplanetary disks around optically visible pre-main sequence stars obtained with a variety of observational techniques, from measurements of scattered light at visual and infrared wavelengths to…

天体物理学 · 物理学 2007-05-23 A. Natta , L. Testi , N. Calvet , Th. Henning , R. Waters , D. Wilner

The results of a numerical study of the growth of solid particles, ranging from 1 micron to 1 millimeter in size, in the vicinity of an azimuthally symmetric density enhancement of a protostellar disk are presented. It is shown that the…

天体物理学 · 物理学 2008-11-26 Nader Haghighipour

Our current understanding of interstellar dust is summarized at an introductory level. Submicron-sized interstellar dust grains absorb and scatter light, and reradiate the absorbed energy in the infrared. The grain population spans a range…

天体物理学 · 物理学 2009-10-31 B. T. Draine

We study the extinction properties of the composite dust grains, consisting of host silicate spheroids and graphite as inclusions, using discrete dipole approximation (DDA). We calculate the extinction cross sections of the composite grains…

太阳与恒星天体物理 · 物理学 2015-06-17 Nisha Katyal , Ranjan Gupta , D B Vaidya

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

It has recently been shown that turbulence in the interstellar medium (ISM) can significantly accelerate the growth of dust grains by accretion of molecules, but the turbulent gas-density distribution also plays a crucial role in shaping…

星系天体物理 · 物理学 2020-10-09 Lars Mattsson

Interstellar dust grains exhibit complex dynamics which is essential for understanding many key interstellar processes that involve dust, including grain alignment, grain growth, grain shattering etc. Grain rotational and translational…

天体物理学 · 物理学 2007-05-23 A. Lazarian , Huirong Yan

The temperature of newly forming dust is controlled by the radiation field. As dust forms around stars, stellar transients, quasars or supernovae, the grains must grow through a regime where they are stochastically heated by individual…

太阳与恒星天体物理 · 物理学 2014-07-31 C. S. Kochanek

Recent measurements of type Ia supernovae indicate that distant supernovae are substantially fainter than expected from the standard flat cold dark matter model. One possible explanation is that the energy density in our universe is in fact…

天体物理学 · 物理学 2007-05-23 Jakob T. Simonsen , Steen Hannestad

Theoretical studies have revealed that dust grains are usually moving fast through the turbulent interstellar gas, which could have significant effects upon interstellar chemistry by modifying grain accretion. This effect is investigated in…

星系天体物理 · 物理学 2015-12-09 J. X. Ge , J. H. He , H. R. Yan

Dust grains in neutral gas behave as aerodynamic particles, so they can develop large density fluctuations independent of gas density fluctuations. Specifically, gas turbulence can drive order-of-magnitude 'resonant' fluctuations in the…

星系天体物理 · 物理学 2015-12-15 Philip F. Hopkins