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We investigate the linear growth and vertical structure of the MRI in protoplanetary discs when dust grains are well mixed with the gas over the entire disc thickness. All the grains have the same radius (a = 0.1, 1 or 3 micron) and…

天体物理学 · 物理学 2009-11-13 Raquel Salmeron , Mark Wardle

Radiative torques on irregular dust grains, in addition to producing superthermal rotation, play a direct dynamical role in the alignment of interstellar dust with the local magnetic field. The equations governing the orientation of…

天体物理学 · 物理学 2009-10-28 B. T. Draine , Joseph C. Weingartner

Grain growth in circumstellar disks is expected to be the first step towards the formation of planetary systems. There is now evidence for grain growth in several disks around young stars. Radially resolved images of grain growth in…

星系天体物理 · 物理学 2015-05-19 A. Banzatti , L. Testi , A. Isella , A. Natta , R. Neri , D. J. Wilner

Outflows of pre-main-sequence stars drive shocks into molecular material within 0.01 - 1 pc of the young stars. The shock-heated gas emits infrared, millimeter and submillimeter lines of many species including. Dust grains are important…

天体物理学 · 物理学 2010-12-13 T. W. Hartquist , S. Van Loo , S. A. E. G. Falle , P. Caselli , I. Ashmore

The timescales on which astronomical dust grows remain poorly understood, with important consequences for our understanding of processes like circumstellar disk evolution and planet formation.A number of post-asymptotic giant branch stars…

太阳与恒星天体物理 · 物理学 2020-03-11 P. Scicluna , F. Kemper , A. Trejo , J. P. Marshall , S. Ertel , M. Hillen

The increasing number of newly detected exoplanets at short orbital periods raises questions about their formation and migration histories. A particular puzzle that requires explanation arises from one of the key results of the Kepler…

地球与行星天体物理 · 物理学 2019-10-16 Mario Flock , Neal J. Turner , Gijs D. Mulders , Yasuhiro Hasegawa , Richard P. Nelson , Bertram Bitsch

Dust grains in low-metallicity star-forming regions may be responsible for the formation of the first low-mass stars. The minimal conditions to activate dust-induced fragmentation require the gas to be pre-enriched above a critical…

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

We investigate the structure of accretion disks around massive protostar applying steady state models of thin disks. The thin disk equations are solved with proper opacities for dust and gas taking into account the huge temperature…

太阳与恒星天体物理 · 物理学 2009-08-17 B. Vaidya , C. Fendt , H. Beuther

Focussing on preplanetary grains growth, we discuss the properties of dust aggregation driven by magnetic dipole forces. While there is no direct evidence for the existence of magnetic grains present in the solar nebula, there are reasons…

天体物理学 · 物理学 2009-11-07 C. Dominik , H. Nuebold

Context. Evaporative (sublimation) cooling of icy interstellar grains occurs when the grains have been suddenly heated by a cosmic-ray (CR) particle or other process. It results in thermal desorption of icy species, affecting the chemical…

星系天体物理 · 物理学 2020-09-09 Juris Kalvāns , Juris Roberts Kalnin

Grain growth by accretion of gas-phase metals is a common assumption in models of dust evolution, but in dense gas, where the timescale is short enough for accretion to be effective, material is accreted in the form of ice mantles rather…

星系天体物理 · 物理学 2021-01-20 F. D. Priestley , I. De Looze , M. J. Barlow

The origin of dust in galaxy halos or in the circum-galactic medium (CGM) is still a mystery. We investigate if the radiation pressure in high-redshift ($z\sim 10$) galaxies can efficiently transport dust to halos. To clarify the first dust…

星系天体物理 · 物理学 2019-05-22 Hiroyuki Hirashita , Akio K. Inoue

In order to explain grain growth to mm sized particles and their retention in outer regions of protoplanetary disks, as it is observed at sub-mm and mm wavelengths, we investigate if strong inhomogeneities in the gas density profiles can…

地球与行星天体物理 · 物理学 2012-02-14 P. Pinilla , T. Birnstiel , L. Ricci , C. P. Dullemond , A. L. Uribe , L. Testi , A. Natta

Measurements by dust detectors on interplanetary spacecraft appear to indicate a substantial flux of interstellar particles with masses exceeding 10^{-12}gram. The reported abundance of these massive grains cannot be typical of interstellar…

天体物理学 · 物理学 2009-11-13 B. T. Draine

A considerable proportion of young stars belong to multiple star systems. Constraining the planet formation processes in multiple stellar systems is then key to understand the global exoplanet population. This study focuses on investigating…

Dust grains influence many aspects of star formation, including planet formation, opacities for radiative transfer, chemistry, and the magnetic field via Ohmic, Hall, and ambipolar diffusion. The size distribution of the dust grains is the…

太阳与恒星天体物理 · 物理学 2023-02-08 Pierre Marchand , Ugo Lebreuilly , Mordecai-Mark Mac Low , Vincent Guillet

Polarization carries information about the magnetic fields in interstellar clouds. The observations of polarized dust emission are used to study the role of magnetic fields in the evolution of molecular clouds and the initial phases of…

星系天体物理 · 物理学 2015-05-13 V. -M. Pelkonen , M. Juvela , P. Padoan

Sticking properties rule the early phases of pebble growth in protoplanetary discs in which grains regularly travel from cold, water-rich regions to the warm inner part. This drift affects composition, grain size, morphology, and water…

地球与行星天体物理 · 物理学 2020-07-03 T. Bogdan , C. Pillich , J. Landers , H. Wende , G. Wurm

Dust particles immersed in a plasma environment become charged through the collection of electrons and ions at random times, causing the dust charge to fluctuate about an equilibrium value. Small grains (with radii less than 1 \mum) or…

等离子体物理 · 物理学 2018-05-16 Lorin S. Matthews , Babak Shotorban , Truell W. Hyde