Article
Astronomy & Astrophysics
O. Schib, C. Mordasini, R. Helled
Summary: This study investigates the formation and evolution of star-disc systems, focusing on early disc sizes and the likelihood of fragmentation. The results show that the early disc size is crucial for fragmentation, which is determined by the mass infall location during the collapse of the molecular cloud core.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Bertram Bitsch, Sean N. Raymond, Lars A. Buchhave, Aaron Bello-Arufe, Alexander D. Rathcke, Aaron David Schneider
Summary: In the pebble accretion scenario, the position of growing planetary cores relative to the water ice line plays a key role in determining the water content of inner planets. Pebbles blocked outside the water ice line result in a dry inner disk, while those blocked inside release water vapor, leading to wetter inner planets.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. Bergez-Casalou, B. Bitsch, S. N. Raymond
Summary: In this study, it is found that the presence of a second planet affects the gas accretion process of both planets when they are accreting from the same disk. The mass ratio of the planets depends on gap formation. If both planets start accreting at the same time, their masses end up being very similar. Delaying the onset of accretion of one planet allows for initially larger mass ratios, but they quickly converge to similar masses. To reproduce the diverse observed mass ratios of exoplanets, the planets must start accreting gas at different times and their accretion must be stopped quickly after the beginning of runaway gas accretion.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
O. Schib, C. Mordasini, N. Wenger, G-D Marleau, R. Helled
Summary: The study reveals that protoplanetary discs are typically very massive early in their formation, with significant differences in average disc masses across the entire stellar population, and variations in disc masses for systems with final stellar mass around 1 solar mass. Despite high initial mass, the inferred total disc lifetimes are long, approximately 5-7 million years, with fragmentation common in hydrodynamic cloud collapse systems, but potentially suppressed in systems limited by magnetic fields.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Ayumu Kuwahara, Hiroyuki Kurokawa, Takayuki Tanigawa, Shigeru Ida
Summary: This study investigates the potential of gas flow induced by low-mass planets to shape the rings and gaps in dust profiles in protoplanetary disks. The results show that the gas outflow toward the outside of the planetary orbit inhibits the radial drift of dust, leading to dust accumulation (the dust ring), while the outflow toward the inside of the planetary orbit enhances the inward drift of dust, causing dust depletion around the planetary orbit (the dust gap). It is suggested that these gas flows induced by low-mass, non-gas-gap-opening planets could be a possible explanation for observed dust substructures in disks.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Urs Schafer, Anders Johansen
Summary: The streaming instability is a promising mechanism for the formation of planetesimals. Through two-dimensional global simulations, it has been found that the vertical shear instability and the streaming instability together can cause sufficient dust concentration for planetesimal formation at lower surface density ratios and smaller dust sizes compared to the streaming instability acting alone.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
J. J. Rucska, J. W. Wadsley
Summary: This article presents the first simulations of the streaming instability (SI) based on a realistic size distribution. The simulations show that kilometre-sized planetesimals can form from the gravitational collapse of pebble clouds. It also reveals a size cutoff for pebbles incorporated into asteroids and comets and warns of potential underestimations of dust mass due to dust clumping and optical depth effects.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Tommy Chi Ho Lau, Joanna Drazkowska, Sebastian M. Stammler, Tilman Birnstiel, Cornelis P. Dullemond
Summary: Research has found that pressure bumps in protoplanetary disks provide favorable locations for the emergence and rapid growth of planetary cores through pebble accretion, due to increased dust density, grain size, and reduced pebble accretion onset mass.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Lucas M. Jordan, Wilhelm Kley, Giovanni Picogna, Francesco Marzari
Summary: This study investigates the dynamics of disks in close binaries, focusing on factors such as disk eccentricity and precession rate. Simulation results show that radiative disks in close binaries become eccentric after an initialization phase, with a slow retrograde precession and generally coherent, rigid precession. The study confirms the robustness of results through a parameter study for different numerical parameters.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
N. Oberg, I. Kamp, S. Cazaux, P. Woitke, W. F. Thi
Summary: This study aims to explore the process of ice formation in circumplanetary disks (CPDs) and constrain the properties of the disk that are consistent with the formation of icy moon systems. The results show that ice can form efficiently in CPDs, and three-body reactions play an important role in water formation. The dust in the CPD midplane needs to be depleted by a factor of 10-50 compared to the circumstellar disk to produce solids with the desired ice to rock ratio of the Galilean satellites. The snowline of the CPD is not affected by radial grain drift, indicating a primordial compositional gradient in the Galilean satellites.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
O. Schib, C. Mordasini, R. Helled
Summary: This article investigates the orbital migration and gas accretion processes of planets in protoplanetary discs. The authors develop a simple prescription for migration and accretion in 1D disc models, calibrated with results from 3D hydrodynamic simulations. The results show that the 1D model is in good agreement with the 3D simulations for a range of parameters.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Paola Pinilla, Christian T. Lenz, Sebastian M. Stammler
Summary: Recent laboratory experiments show that lower fragmentation velocities of icy dust particles can impact planet formation, making it difficult for pebble-sized particles to form in protoplanetary disks. By studying dust evolution models and observing protoplanetary disks, a better understanding of the basic features and structures of these disks can be gained through different combinations of particle and gas diffusion parameters.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
P. Pinilla, N. T. Kurtovic, M. Benisty, C. F. Manara, A. Natta, E. Sanchis, M. Tazzari, S. M. Stammler, L. Ricci, L. Testi
Summary: The frequency of Earth-sized planets in habitable zones appears to be higher around M-dwarfs, making these systems exciting laboratories to investigate planet formation. Observations of protoplanetary disks around very low-mass stars and brown dwarfs remain challenging and little is known about their properties. The characteristics of the disk around CIDA 1 challenge current dust evolution models, particularly processes like fragmentation, growth, and diffusion of particles inside pressure bumps.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Ryuki Hyodo, Tristan Guillot, Shigeru Ida, Satoshi Okuzumi, Andrew N. Youdin
Summary: This study investigates the local pile-up of silicate dust and pebbles around the snow line, providing insights into the disk conditions for solid accumulation inside and outside the snow line with different parameters.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
M. Lehmann, M-K Lin
Summary: The standard core accretion model for planetesimal formation in protoplanetary discs faces challenges due to the vertical settling of dust against turbulent stirring. The vertical shear instability (VSI), sustaining turbulence in the outer regions of PPDs, drives the formation of long-lived vortices that can collect dust and potentially trigger the streaming instability (SI). The presence of pressure bumps in the discs can lead to the formation of dusty vortices with high dust-to-gas ratios, impacting the vertical mass flow profile and alpha viscosity values.
ASTRONOMY & ASTROPHYSICS
(2022)