scholarly journals Planet formation in evolving protoplanetary discs

2013 ◽  
Vol 8 (S299) ◽  
pp. 179-189 ◽  
Author(s):  
Richard Alexander
Keyword(s):  
Planet Formation ◽  
And Migration ◽  
Protoplanetary Discs

AbstractI attempt to summarize our knowledge of planet formation in evolving protoplanetary discs. I first review the physics of disc evolution and dispersal. For most of the disc lifetime evolution is driven by accretion and photoevaporation, and I discuss how the interplay between these processes shapes protoplanetary discs. I also discuss the observations that we use to test these models, and the major uncertainties that remain. I will then move on to consider planet formation and migration in evolving discs, and discuss how observations of both discs and planets can be used to inform our understanding of protoplanetary disc evolution.

scholarly journals Giant Planet Formation and Migration

2018 ◽  
Vol 214 (1) ◽  
Author(s):  
Sijme-Jan Paardekooper ◽  
Anders Johansen
Keyword(s):  
Planet Formation ◽  
Giant Planet ◽  
And Migration

The dance of snow-lines

2020 ◽  
Author(s):  
James Owen
Keyword(s):  
High Resolution ◽  
Planet Formation ◽  
Solid Phase ◽  
Outer Region ◽  
Vapour Phase ◽  
Vital Role ◽  
Sublimation Temperature ◽  
New Process ◽  
High Resolution Images ◽  
Protoplanetary Discs

<p>Snow-lines are thought to play a vital role in the evolution of protoplanetary discs and planet formation at all scales. Snow-lines occur in regions of the protoplanetary discs where the temperature reaches the sublimation temperature and volatiles transition from the solid phase to the vapour phase (or vice-versa). However, in the outer region of protoplanetary discs (beyond a few AU), the temperature is set by the distribution of solids and their ability to absorb stellar light. Thus, the thermodynamics of the disc and the volatile phases are inextricably linked. In this talk, I will show this coupling is thermally unstable, and snow-lines continually evolve in regions of the disc that are marginally optically thick. Patches of the disc proceeding through a limit cycle, where volatiles in a region of the disc continually condense and then sublimate. Using numerical simulations of the CO snow-line I will show it can move 10s AU over 10,000 years, repeatedly. I will use these simulations to discuss how this new process may effect measured Carbon abundances, solid evolution and ultimately planet formation, making connections to high-resolution images of protoplanetary discs. </p>

scholarly journals The Rossiter-McLaughlin effect for exoplanets

2010 ◽  
Vol 6 (S276) ◽  
pp. 230-237
Author(s):  
Joshua N. Winn
Keyword(s):  
Measurement Technique ◽  
Planet Formation ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
History Of ◽  
And Migration

AbstractThere are now more than 35 stars with transiting planets for which the stellar obliquity—or more precisely its sky projection—has been measured, via the eponymous effect of Rossiter and McLaughlin. The history of these measurements is intriguing. For 8 years a case was gradually building that the orbits of hot Jupiters are always well-aligned with the rotation of their parent stars. Then in a sudden reversal, many misaligned systems were found, and it now seems that even retrograde systems are not uncommon. I review the measurement technique underlying these discoveries, the patterns that have emerged from the data, and the implications for theories of planet formation and migration.

scholarly journals Protoplanetary disc evolution in magnetically layered disc models

2004 ◽  
Vol 202 ◽  
pp. 319-321
Author(s):  
Philip J. Armitage
Keyword(s):  
Angular Momentum ◽  
Planet Formation ◽  
Momentum Transport ◽  
Magnetohydrodynamic Turbulence ◽  
Angular Momentum Transport ◽  
And Migration ◽  
Self Gravity

I discuss protoplanetary disc evolution under the assumption that magnetohydrodynamic turbulence and self-gravity are the sole sources of angular momentum transport. This assumption implies a magnetically layered disc structure which leads to unsteady accretion, and larger disc masses at late epochs. The resulting environment for planet formation and migration differs qualitatively from the highly simplified – almost toy – models often adopted.

scholarly journals Gas composition of the main volatile elements in protoplanetary discs and its implication for planet formation

2015 ◽  
Vol 574 ◽  
pp. A138 ◽  
Author(s):  
A. Thiabaud ◽  
U. Marboeuf ◽  
Y. Alibert ◽  
I. Leya ◽  
K. Mezger
Keyword(s):  
Planet Formation ◽  
Gas Composition ◽  
Volatile Elements ◽  
Protoplanetary Discs

scholarly journals On the vortex evolution in non-isothermal protoplanetary discs

2020 ◽  
Vol 493 (2) ◽  
pp. 3014-3025
Author(s):  
D Tarczay-Nehéz ◽  
Zs Regály ◽  
E Vorobyov
Keyword(s):  
Large Scale ◽  
Planet Formation ◽  
Dead Zone ◽  
Giant Planet ◽  
Building Blocks ◽  
Outer Edge ◽  
Wave Instability ◽  
Large Scale Vortex ◽  
Self Gravity ◽  
Protoplanetary Discs

ABSTRACT It is believed that large-scale horseshoe-like brightness asymmetries found in dozens of transitional protoplanetary discs are caused by anticyclonic vortices. These vortices can play a key role in planet formation, as mm-sized dust – the building blocks of planets – can be accumulated inside them. Anticyclonic vortices are formed by the Rossby wave instability, which can be excited at the gap edges opened by a giant planet or at sharp viscosity transitions of accretionally inactive regions. It is known that vortices are prone to stretching and subsequent dissolution due to disc self-gravity for canonical disc masses in the isothermal approximation. To improve the hydrodynamic model of protoplanetary discs, we include the disc thermodynamics in our model. In this paper, we present our results on the evolution of the vortices formed at the outer edge of an accretionally inactive region (dead zone) assuming an ideal equation of state and taking PdV work, disc cooling in the β-approximation, and disc self-gravity into account. Thermodynamics affects the offset and the mode number (referring to the number of small vortices at the early phase) of the RWI excitation, as well as the strength, shape, and lifetime of the large-scale vortex formed through merging of the initial small vortices. We found that the inclusion of gas thermodynamics results in stronger, however decreased lifetime vortices. Our results suggest that a hypothetical vortex-aided planet formation scenario favours effectively cooling discs.

scholarly journals TW Hya: an old protoplanetary disc revived by its planet

2020 ◽  
Author(s):  
Sergei Nayakshin ◽  
Takashi Tsukagoshi ◽  
Cassandra Hall ◽  
Allona Vazan ◽  
Ravit Helled ◽  
...  
Keyword(s):  
Planet Formation ◽  
Gravitational Instability ◽  
Giant Planet ◽  
Emission Feature ◽  
Time Dependent ◽  
Dust Particles ◽  
Dark Ring ◽  
Build Time ◽  
Core Accretion ◽  
Protoplanetary Discs

Abstract Dark rings with bright rims are the indirect signposts of planets embedded in protoplanetary discs. In a recent first, an azimuthally elongated AU-scale blob, possibly a planet, was resolved with ALMA in TW Hya. The blob is at the edge of a cliff-like rollover in the dust disc rather than inside a dark ring. Here we build time-dependent models of TW Hya disc. We find that the classical paradigm cannot account for the morphology of the disc and the blob. We propose that ALMA-discovered blob hides a Neptune mass planet losing gas and dust. We show that radial drift of mm-sized dust particles naturally explains why the blob is located on the edge of the dust disc. Dust particles leaving the planet perform a characteristic U-turn relative to it, producing an azimuthally elongated blob-like emission feature. This scenario also explains why a 10 Myr old disc is so bright in dust continuum. Two scenarios for the dust-losing planet are presented. In the first, a dusty pre-runaway gas envelope of a ∼40 M⊕ Core Accretion planet is disrupted, e.g., as a result of a catastrophic encounter. In the second, a massive dusty pre-collapse gas giant planet formed by Gravitational Instability is disrupted by the energy released in its massive core. Future modelling may discriminate between these scenarios and allow us to study planet formation in an entirely new way – by analysing the flows of dust and gas recently belonging to planets, informing us about the structure of pre-disruption planetary envelopes.

scholarly journals Ice Condensation as a Planet Formation Mechanism

2013 ◽  
Vol 8 (S299) ◽  
pp. 382-383
Author(s):  
Katrin Ros
Keyword(s):  
Formation Mechanism ◽  
Time Scale ◽  
Planet Formation ◽  
Particle Growth ◽  
Dynamical Behaviour ◽  
Water Ice ◽  
Ice Particles ◽  
Size Evolution ◽  
Protoplanetary Discs

AbstractParticles in protoplanetary discs grow rapidly to millimetre-sizes via coagulation, but further growth to centimetre-sized pebbles is not yet completely understood. We investigate particle growth by ice condensation in a model where we take the dynamical behaviour of vapour and ice particles into account, as well as the size evolution due to condensation and sublimation. Our results show that efficient growth from dust to pebbles is possible close to the water ice line at ~3 AU, with particles growing from millimetres to decimetres on a time scale of 10000 yr.

scholarly journals Influence of growth on dust settling and migration in protoplanetary discs

2010 ◽  
Vol 6 (S276) ◽  
pp. 405-406
Author(s):  
Elisabeth Crespe ◽  
Jean-Francois Gonzalez ◽  
Guillaume Laibe ◽  
Sarah T. Maddison ◽  
Laure Fouchet
Keyword(s):  
Growth Rate ◽  
Central Star ◽  
Constant Growth Rate ◽  
Grain Growth Model ◽  
Dust Dynamics ◽  
And Migration ◽  
Dust Distribution ◽  
Constant Growth ◽  
Gas Drag ◽  
Protoplanetary Discs

AbstractTo form meter-sized pre-planetesimals in protoplanetary discs, dust aggregates have to decouple from the gas at a distance far enough from the central star so they are not accreted. Dust grains are affected by gas drag, which results in a vertical settling towards the mid-plane, followed by radial migration. To have a better understanding of the influence of growth on the dust dynamics, we use a simple grain growth model to determine the dust distribution in observed discs. We implement a constant growth rate into a gas+dust hydrodynamics SPH code and vary the growh rate to study the resulting effect on dust distribution. The growth rate allows us to determine the relative importance between friction and growth.We show that depending on the growth rate, a range of dust distribution can result. For large enough growth rates, grains can decouple from the gas before being accreted onto the central star, thus contributing as planetary building rocks.

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