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We show that condensation is an efficient particle growth mechanism, leading to growth beyond decimeter-sized pebbles close to an ice line in protoplanetary discs. As coagulation of dust particles is frustrated by bouncing and…

Earth and Planetary Astrophysics · Physics 2015-06-15 Katrin Ros , Anders Johansen

We improve on our previous treatments of long-term evolution of protostellar disks by explicitly solving disk self-gravity in two dimensions. The current model is an extension of the one-dimensional layered accretion disk model of Bae et…

Solar and Stellar Astrophysics · Physics 2015-06-22 Jaehan Bae , Lee Hartmann , Zhaohuan Zhu , Richard P. Nelson

Proto-planetary discs, the birth environment of planets, are an example of a structure commonly found in astrophysics, accretion discs. Identifying the mechanism responsible for accretion is a long-standing problem, dating back several…

Earth and Planetary Astrophysics · Physics 2023-04-04 Giovanni P. Rosotti

For the investigation of collisions among protoplanetesimal dust aggregates, we performed microgravity experiments in which the impacts of high-porosity mm-sized dust aggregates into 2.5 cm-sized high-porosity dust aggregates can be…

Astrophysics · Physics 2009-11-13 Doreen Langkowski , Jens Teiser , Jürgen Blum

We perform high-resolution (15-30 pc) adaptive mesh simulations to study the impact of momentum-driven AGN feedback in cool-core clusters, focusing in this paper on the formation of cold clumps. The feedback is jet-driven with an energy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Yuan Li , Greg L. Bryan

We present a detailed computational study of the assembly of protostellar disks and massive stars in molecular clouds with supersonic turbulence. We follow the evolution of large scale filamentary structures in a cluster-forming clump down…

Astrophysics · Physics 2009-11-11 Robi Banerjee , Ralph E. Pudritz , Dave W. Anderson

The standard accretion discs are known to be thermally and viscously unstable over a certain range of temperatures. In the inner disc regions there may develop radiation pressure driven instability, which is possibly related to the rapid…

Astrophysics · Physics 2007-05-23 Agnieszka Janiuk , Bozena Czerny

Recent observations of protostellar cores suggest that most of the material in the protostellar phase is accreted along streamers. Streamers in this context are defined as velocity coherent funnels of denser material potentially connecting…

Astrophysics of Galaxies · Physics 2024-06-19 Stefan Heigl , Elena Hoemann , Andreas Burkert

Evidence for the accretion of cold gas in galaxies has been rapidly accumulating in the past years. HI observations of galaxies and their environment have brought to light new facts and phenomena which are evidence of ongoing or recent…

Astrophysics · Physics 2009-06-23 R. Sancisi , F. Fraternali , T. Oosterloo , J. M. van der Hulst

Beyond the snow line of protoplanetary discs and inside the dense core of molecular clouds, the temperature of gas is low enough for water vapour to condense into amorphous ices on the surface of preexisting refractory dust particles.…

Gas and dust in inclined orbits around binaries experience precession induced by the binary gravitational torque. The difference in precession between gas and dust alters the radial drift of weakly coupled dust and leads to density…

Earth and Planetary Astrophysics · Physics 2021-10-13 Hossam Aly , Jean-François Gonzalez , Rebecca Nealon , Cristiano Longarini , Giuseppe Lodato , Daniel J. Price

The thermal instability of accretion disks is widely used to explain the activity of cataclysmic variables, but its development in protoplanetary disks has been studied in less detail. We present a semi-analytical stationary model for…

Earth and Planetary Astrophysics · Physics 2023-07-31 Ya. N. Pavlyuchenkov , V. V. Akimkin , A. P. Topchieva , E. I. Vorobyov

Dusty disks around young stars are formed out of interstellar dust that consists of amorphous, submicrometre grains. Yet the grains found in comets and meteorites, and traced in the spectra of young stars, include large crystalline grains…

Earth and Planetary Astrophysics · Physics 2010-11-02 Dejan Vinkovic

Young protostellar discs are likely to be both self-gravitating, and to support grain growth to sizes where the particles decoupled from the gas. This combination could lead to short-wavelength fragmentation of the solid component in…

Earth and Planetary Astrophysics · Physics 2023-05-17 Cristiano Longarini , Philip J. Armitage , Giuseppe Lodato , Daniel J. Price , Simone Ceppi

The temperature in most parts of a protoplanetary disk is determined by irradiation from the central star. Numerical experiments of Watanabe \& Lin (2008) suggested that such disks, also called `passive disks', suffer from a thermal…

Earth and Planetary Astrophysics · Physics 2021-12-22 Yanqin Wu , Yoram Lithwick

Black hole accretion flows can be divided into two broad classes: cold and hot. Cold accretion flows, which consist of cool optically thick gas, are found at relatively high mass accretion rates. Prominent examples are the standard thin…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Feng Yuan , Ramesh Narayan

The accretion process onto spinning objects in Kerr spacetimes is studied with numerical simulations. Our results show that accretion onto compact objects with Kerr parameter (characterizing the spin) $|a| < M$ and $|a| > M$ is very…

General Relativity and Quantum Cosmology · Physics 2009-11-18 Cosimo Bambi , Katherine Freese , Tomohiro Harada , Rohta Takahashi , Naoki Yoshida

We extend our previous numerical simulation of accretion disks with shock waves when cooling effects are also included. We consider bremsstrahlung and other power law processes: $\Lambda \propto T^{\alpha} \rho^2$ to mimic cooling in our…

Astrophysics · Physics 2009-10-28 Diego M. Molteni , H. Sponholz , Sandip K. Chakrabarti

Chondrules are thought to have formed during transient flash-heating events in dust-enriched regions of the solar protoplanetary disk. Although laboratory studies have characterized the oxygen isotopic compositions of chondritic materials,…

Earth and Planetary Astrophysics · Physics 2026-04-29 Sota Arakawa , Takayuki Ushikubo , Ryosuke T. Tominaga

The final stage of gas giant formation involves accreting gas from the parent protoplanetary disk. In general, the infalling gas likely approaches a free-fall velocity, creating an accretion shock, leading to strong shock heating and…

Earth and Planetary Astrophysics · Physics 2022-02-09 Zhuo Chen , Xue-Ning Bai