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相关论文: Modelling heterogeneous dust particles. An applica…

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We study the light scattering properties of moderately large dust aggregates ($0.8\mu m \lesssim R \lesssim 2.0\mu m$) with a wide variation of porosity ($\mathcal{P}$) from 0.57 to 0.98. The computations are performed using the…

地球与行星天体物理 · 物理学 2017-09-28 P. Deb Roy , P. Halder , H. S. Das

We report optical imaging, optical and near-infrared polarimetry, and Spitzer mid-infrared spectroscopy of comet C/2007 N3 (Lulin). Polarimetric observations were obtained in R (0.676 micron) at phase angles from 0.44 degrees to 21 degrees…

The interstellar traveler, 2I/Borisov, is the first clearly active extrasolar comet, ever detected in our Solar system. We obtained high-resolution interferometric observations of 2I/Borisov with the Atacama Large Millimeter/submillimeter…

We use high-resolution N-body simulations to study the equilibrium density profiles of dark matter halos in hierarchically clustering universes. We find that all such profiles have the same shape, independent of halo mass, of initial…

天体物理学 · 物理学 2008-11-26 Julio F. Navarro , Carlos S. Frenk , Simon D. M. White

Context: Sticking of colliding dust particles through van der Waals forces is the first stage in the grain growth process in protoplanetary disks, eventually leading to the formation of comets, asteroids and planets. A key aspect of the…

天体物理学 · 物理学 2009-11-11 C. W. Ormel , M. Spaans , A. G. G. M. Tielens

We present new interstellar dust models which have been derived by simultaneously fitting the far-ultraviolet to near-infrared extinction, the diffuse infrared (IR) emission and, unlike previous models, the elemental abundance constraints…

天体物理学 · 物理学 2011-07-18 Viktor Zubko , Eli Dwek , Richard G. Arendt

We have modelled Atacama Large Millimeter/sub-millimeter Array (ALMA) long baseline imaging of the strong gravitational lens system H-ATLAS J090311.6+003906 (SDP.81). We have reconstructed the distribution of band 6 and 7 continuum emission…

Compressive strength is a key to understanding the internal structure of dust aggregates in protoplanetary disks and their resultant bodies, such as comets and asteroids in the Solar System. Previous work has modeled the compressive…

地球与行星天体物理 · 物理学 2023-08-09 Misako Tatsuuma , Akimasa Kataoka , Satoshi Okuzumi , Hidekazu Tanaka

The dust sub-millimetre polarisation of star-forming clouds carries information on dust and the role of magnetic fields in cloud evolution. With observations of a dense filamentary cloud G035.39-00.33, we aim to characterise the dust…

We probe the region around the protostar HH108MMS by deep mid infrared photometric and polarimetric imaging. The protostar is detected at 14mu in absorption against the diffuse background. Next to HH108MMS, we find a second absorbing core,…

天体物理学 · 物理学 2007-05-23 R. Siebenmorgen , E. Kruegel

While marginal in mass terms, dust grains play an outsized role in both the physics and observation of the interstellar medium (ISM). However, explicit modelling of this ISM constituent remains uncommon in large cosmological simulations. In…

We aim at constraining the dust mass in high-redshift ($z\gtrsim 5$) galaxies using the upper limits obtained by ALMA in combination with the rest-frame UV--optical spectral energy distributions (SEDs). For SED fitting, because of…

星系天体物理 · 物理学 2017-10-18 Hiroyuki Hirashita , Denis Burgarella , Rychard J. Bouwens

Molecular clouds are regions of dense gas and dust in space where new stars and planets are born. There is a strong correlation between the distribution of dust and molecular gas in molecular clouds. The present work focuses on the…

星系天体物理 · 物理学 2024-10-28 Rui-Zhi Li , Bing-Qiu Chen , Guang-Xing Li , Bo-Ting Wang , Hao-Ming Ren , Qi-Ning Guo

We report high angular resolution (3") Submillimeter Array (SMA) observations of the molecular cloud associated with the Ultra-Compact HII region G5.89-0.39. Imaged dust continuum emission at 870 micron reveals significant linear…

天体物理学 · 物理学 2011-02-11 Ya-Wen Tang , Paul T. P. Ho , Josep Miquel Girart , Ramprasad Rao , Patrick Koch , Shih-Ping Lai

Spatial association of clumps from different tracers turns out to be a valuable tool to determine the physical properties of molecular clouds. It provides a reliable estimate for the $X$-factors, serves to trace the density of clumps seen…

We report results from broadband visible images of comet C/2012 S1 (ISON) obtained with the Hubble Space Telescope Wide Field Camera 3 on 2013 April 10. C/ISON's coma brightness follows a 1/{\rho} (where {\rho} is the projected distance…

Dust transport and deposition behind larger boulders on the comet 67P/Churyumov-Gerasimenko (67P/C-G) have been observed by the Rosetta mission. We present a mechanism for dust transport vectors based on a homogenous surface activity model…

地球与行星天体物理 · 物理学 2016-06-28 Tobias Kramer , Matthias Noack

We analyse the possible contribution of topological defects to cosmic microwave anisotropies, both temperature and polarisation. We allow for the presence of both inflationary scalars and tensors, and of polarised dust foregrounds that may…

宇宙学与河外天体物理 · 物理学 2014-11-11 Joanes Lizarraga , Jon Urrestilla , David Daverio , Mark Hindmarsh , Martin Kunz , Andrew R. Liddle

To date, at least three comets -- 2I/Borisov, C/2016 R2 (PanSTARRS), and C/2009 P1 (Garradd) -- have been observed to have unusually high CO concentrations compared to water. We attempt to explain these observations by modeling the effect…

地球与行星天体物理 · 物理学 2021-05-26 Ellen M. Price , L. Ilsedore Cleeves , Dennis Bodewits , Karin I. Öberg