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The formation of planets depends on the underlying protoplanetary disc structure, which influences both the accretion and migration rates of embedded planets. The disc itself evolves on time-scales of several Myr during which both…

Earth and Planetary Astrophysics · Physics 2018-02-07 Bertram Bitsch , Michiel Lambrechts , Anders Johansen

Observations of massive stars within the central parsec of the Galaxy show that, while most stars orbit within a well-defined disc, a significant fraction have large eccentricities and / or inclinations with respect to the disc plane. Here,…

Astrophysics · Physics 2009-03-08 Jorge Cuadra , Philip J. Armitage , Richard D. Alexander

We have searched a sample of 151 young, energetic pulsars for periodic variation in pulse time-of-arrival arising from the influence of planetary companions. We are sensitive to objects with masses two orders of magnitude lower than those…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Matthew Kerr , Simon Johnston , George Hobbs , Ryan M. Shannon

Many theoretical studies have shown that external photoevaporation from massive stars can severely truncate, or destroy altogether, the gaseous protoplanetary discs around young stars. In tandem, several observational studies report a…

Earth and Planetary Astrophysics · Physics 2021-09-22 Richard J. Parker , Hayley L. Alcock , Rhana B. Nicholson , Olja Panić , Simon P. Goodwin

We applied the global end-to-end model described in Paper~I of this series to perform a population synthesis of companions formed via disc instability (DI). By using initial conditions compatible with both observations and hydrodynamical…

Earth and Planetary Astrophysics · Physics 2026-01-14 O. Schib , C. Mordasini , A. Emsenhuber , R. Helled

Protoplanetary disks have been found around free-floating objects with masses comparable to those of giant planets. The frequency and properties of these disks around planetary-mass objects are still debated. Here we present ultradeep…

Solar and Stellar Astrophysics · Physics 2025-01-28 Holly Hanbee Seo , Aleks Scholz

The existence of giant planets on wide orbits ($\stackrel{>}{_\sim}100$AU) challenge planet formation theories; the core accretion scenario has difficulty in forming them, whereas the disc instability model forms an overabundance of them…

Earth and Planetary Astrophysics · Physics 2023-08-09 Ethan Carter , Dimitris Stamatellos

The dominant formation mechanism of brown dwarfs and planetary mass objects in star-forming regions is presently uncertain. Do they form like stars, via the collapse and fragmentation of cores in Giant Molecular clouds, or do they form like…

Solar and Stellar Astrophysics · Physics 2023-08-16 Richard J. Parker , Catarina Alves de Oliveira

The radial velocities and direct imaging observations of exoplanets have suggested that the frequency of giant planets may decrease for intermediate-mass stars ($2.5-8\,M_\odot$). The key mechanism that could hinder their formation remains…

Earth and Planetary Astrophysics · Physics 2022-06-22 Paola Pinilla , Antonio Garufi , Matías Gárate

A major outstanding question regarding the formation of planetary systems is whether wide-orbit giant planets form differently than close-in giant planets. We aim to establish constraints on two key parameters that are relevant for…

Earth and Planetary Astrophysics · Physics 2019-07-29 Kevin Wagner , Dániel Apai , Kaitlin M. Kratter

We use resistive magnetohydrodynamical simulations with the nested grid technique to study the formation of protoplanetary disks around protostars from molecular cloud cores that provide the realistic environments for planet formation. We…

Earth and Planetary Astrophysics · Physics 2015-05-14 Shu-ichiro Inutsuka , Masahiro N. Machida , Tomoaki Matsumoto

We numerically studied close encounters between a young stellar system hosting a massive, gravitationally fragmenting disk and an intruder diskless star with the purpose to determine the evolution of fragments that have formed in the disk…

Solar and Stellar Astrophysics · Physics 2018-01-10 Eduard I. Vorobyov , Maria Steinrueck , Vardan Elbakyan , Manuel Guedel

The study of protoplanetary disc evolution and planet formation has mainly concentrated on solar (and low) mass stars since they host the majority of the confirmed exoplanets. Nevertheless, the numerous planets found orbiting stars up to…

Earth and Planetary Astrophysics · Physics 2023-11-08 María Paula Ronco , Matthias R. Schreiber , Eva Villaver , Octavio M. Guilera , Marcelo M. Miller Bertolami

Simulations show that the orbits of planets are readily disrupted in dense star-forming regions; planets can be exchanged between stars, become free-floating and then be captured by other stars. However, dense star-forming regions also tend…

Earth and Planetary Astrophysics · Physics 2022-10-12 Emma C. Daffern-Powell , Richard J. Parker

We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation.…

Solar and Stellar Astrophysics · Physics 2018-01-25 Matthew R. Bate

We present a semi-analytic model for the growth, drift, desorption, and fragmentation of millimeter- to meter-sized particles in protoplanetary disks. Fragmentation occurs where particle collision velocities exceed critical fragmentation…

Earth and Planetary Astrophysics · Physics 2024-01-12 Elizabeth Yunerman , Diana Powell , Ruth Murray-Clay

Observations of circumstellar disks around stars as a function of stellar properties such as mass, metallicity, multiplicity, and age, provide constraints on theories concerning the formation and evolution of planetary systems. Utilizing…

Earth and Planetary Astrophysics · Physics 2015-05-13 Michael R. Meyer

Gravitationally unstable disks can fragment and form bound objects provided that their cooling time is short. In protoplanetary disks radiative cooling is likely to be too slow to permit formation of planets by fragmentation within several…

Astrophysics · Physics 2011-02-11 Roman R. Rafikov

The formation of planetary cores must proceed rapidly in order for the giant planets to accrete their gaseous envelopes before the dissipation of the protoplanetary gas disc (<3 Myr). In orbits beyond 10 AU, direct accumulation of…

Earth and Planetary Astrophysics · Physics 2016-04-05 Michiel Lambrechts , Anders Johansen

Observations indicate that the gaseous circumstellar disks around young stars vary significantly in size, ranging from tens to thousands of AU. Models of planet formation depend critically upon the properties of these primordial disks, yet…

Solar and Stellar Astrophysics · Physics 2015-06-04 K. A. Kretke , H. F. Levison , M. W. Buie , A. Morbidelli
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