scholarly journals Planetary embryo collisions and the wiggly nature of extreme debris discs

2021 ◽  
Vol 502 (2) ◽  
pp. 2984-3002
Author(s):  
Lewis Watt ◽  
Zoe Leinhardt ◽  
Kate Y L Su
Keyword(s):  
Equations Of State ◽  
Semimajor Axis ◽  
Central Star ◽  
Impact Angle ◽  
Narrow Region ◽  
Term Variation ◽  
Planetary Embryo ◽  
Smoothed Particle ◽  
Giant Impacts ◽  
Post Impact

ABSTRACT In this paper, we present results from a multistage numerical campaign to begin to explain and determine why extreme debris disc detections are rare, what types of impacts will result in extreme debris discs and what we can learn about the parameters of the collision from the extreme debris discs. We begin by simulating many giant impacts using a smoothed particle hydrodynamical code with tabulated equations of state and track the escaping vapour from the collision. Using an N-body code, we simulate the spatial evolution of the vapour generated dust post-impact. We show that impacts release vapour anisotropically not isotropically as has been assumed previously and that the distribution of the resulting generated dust is dependent on the mass ratio and impact angle of the collision. In addition, we show that the anisotropic distribution of post-collision dust can cause the formation or lack of formation of the short-term variation in flux depending on the orientation of the collision with respect to the orbit around the central star. Finally, our results suggest that there is a narrow region of semimajor axis where a vapour generated disc would be observable for any significant amount of time implying that giant impacts where most of the escaping mass is in vapour would not be observed often but this does not mean that the collisions are not occurring.

scholarly journals Formation of heavy element rich giant planets by giant impacts

2007 ◽  
Vol 3 (S249) ◽  
pp. 267-270
Author(s):  
H. Genda ◽  
M. Ikoma ◽  
T. Guillot ◽  
S. Ida
Keyword(s):  
Total Mass ◽  
Heavy Element ◽  
Theoretical Models ◽  
Impact Angle ◽  
Giant Planets ◽  
Hot Jupiters ◽  
Smoothed Particle ◽  
Giant Impacts ◽  
Gas Giant ◽  
Smoothed Particle Hydrodynamic

AbstractWe have performed the smoothed particle hydrodynamic (SPH) simulations of collisions between two gas giant planets. Changes in masses of the ice/rock core and the H/He envelope due to the collisions are investigated. The main aim of this study is to constrain the origin and probability of a class of extrasolar hot Jupiters that have much larger cores and/or higher core/envelope mass ratios than those predicted by theories of accretion of gas giant planets. A typical example is HD 149026b. Theoretical models of the interior of HD 149026b (Sato et al. 2005; Fortney et al. 2006; Ikoma et al. 2006) predict that the planet contains a huge core of 50-80 Earth masses relative to the total mass of 110 Earth masses. Our SPH simulations demonstrate that such a gas giant is produced by a collision with an impact velocity of typically more than 2.5 times escape velocity and an impact angle of typically less than 10 degrees, which results in an enormous loss of the envelope gas and complete accretion of both cores.

Theoretical predictions of mass, semimajor axis and eccentricity distributions of super-Earths

2010 ◽  
Vol 6 (S276) ◽  
pp. 64-71
Author(s):  
Shigeru Ida
Keyword(s):  
Semimajor Axis ◽  
Mass Range ◽  
Model Parameters ◽  
Type I ◽  
Orbital Eccentricity ◽  
Resonant Orbits ◽  
Theoretical Predictions ◽  
Giant Impacts ◽  
Solar Type ◽  
Host Stars

AbstractWe discuss the effects of close scattering and merging between planets on distributions of mass, semimajor axis and orbital eccentricity, using population synthesis model of planet formation, focusing on the distributions of close-in super-Earths, which are being observed recently. We found that a group of compact embryos emerge interior to the ice line, grow, migrate, and congregate into closely-packed convoys which stall in the proximity of their host stars. After the disk-gas depletion, they undergo orbit crossing, close scattering, and giant impacts to form multiple rocky Earths or super-Earths in non-resonant orbits around ~ 0.1AU with moderate eccentricities of ~ 0.01–0.1. The formation of these planets does not depend on model parameters such as type I migration speed. The fraction of solar-type stars with these super-Earths is anti-correlated with the fraction of stars with gas giants. The newly predicted family of close-in super-Earths makes less clear “planet desert” at intermediate mass range than our previous prediction.

Analysis of surface-erosion mechanism due to impacts of freely rotating angular particles using smoothed particle hydrodynamics erosion model

2017 ◽  
Vol 231 (12) ◽  
pp. 1537-1551 ◽  
Author(s):  
Xiangwei Dong ◽  
Zengliang Li ◽  
Qi Zhang ◽  
Wei Zeng ◽  
G.R. Liu
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Impact Angle ◽  
Surface Erosion ◽  
Free Rotation ◽  
Erosion Model ◽  
Erosion Mechanism ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact ◽  
Angular Particles

The free rotation of an angular particle during its impact on ductile surfaces is an important factor that influences the erosion mechanism. However, the phenomenon cannot be easily revealed experimentally because the incident conditions cannot be accurately controlled. In this study, a novel erosion model based on smoothed particle hydrodynamics method is proposed to simulate single and multiple impacts of particles with specified angularities on a ductile surface. The model can simulate a particle having free rotation during the impact process and initial rotation prior to the impact. The results show that the impact angle and initial orientation significantly affect the tumbling behavior, which determines the erosion mechanism. Moreover, the initial rotation is investigated by assigning an initial angular velocity to the particle at the onset of impact. The proposed smoothed particle hydrodynamics erosion model is proven to be a promising complementary method that supports experimental techniques. This study provides insight for understanding the fundamental mechanisms of surface erosion due to angular particles.

AN IMPLEMENTATION OF THE SMOOTHED PARTICLE HYDRODYNAMICS FOR HYPERVELOCITY IMPACTS AND PENETRATION TO LAYERED COMPOSITES

2013 ◽  
Vol 10 (03) ◽  
pp. 1350056 ◽  
Author(s):  
G. R. LIU ◽  
C. E. ZHOU ◽  
G. Y. WANG
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
High Velocity ◽  
Numerical Solutions ◽  
Equations Of State ◽  
Damage Model ◽  
High Rate ◽  
Material Strength ◽  
Layered Composites ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Driven by applications in the design of protective structure systems, the need to model high velocity impact is becoming of great importance. This paper presents a Smoothed Particle Hydrodynamics (SPH) procedure for 3D simulation of high velocity impacts where high rate hydrodynamics and material strength are of great concern. The formulations and implementations of the Johnson–Cook strength and damage model considering temperature effect, and Mie–Gruneison and Tilloton equations of state are discussed. The performance of the procedure is demonstrated through two example analyses, one modeling a cubic tungsten projectile penetrating a multi-layered target panel and the other involving a sphere perforating a thin plate. The results obtained, with comparisons made to both experimental results and other numerical solutions previously reported, show that our SPH-3D implementation is accurate and reliable for modeling the overall behavior of the high rate hydrodynamics with material strength.

scholarly journals Numerical Simulation of Impact Behavior of Ceramic Coatings Using Smoothed Particle Hydrodynamics Method

2020 ◽  
pp. 1-25
Author(s):  
Jian Zhang ◽  
Zhe Lu ◽  
Sugrim Sagar ◽  
Hyunhee Choi ◽  
Heesung Park ◽  
...  
Keyword(s):  
Spherical Particle ◽  
Smoothed Particle Hydrodynamics ◽  
Coating Layer ◽  
Ceramic Coatings ◽  
Impact Angle ◽  
Impact Behavior ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Abstract In this work, the impact behavior of an alumina spherical particle on alumina coating is modeled using the smoothed particle hydrodynamics (SPH) method. The effects of impact angle (0°, 30°, and 60°) and velocity (100 m/s, 200 m/s, and 300 m/s) on the morphology changes of the impact pit and impacting particle, and their associated stress and energy are investigated. The results show that the combination of impact angle of 0° and velocity of 300 m/s produces the highest penetration depth and largest stress and deformation in the coating layer, while the combination of 100 m/s & 60° causes the minimum damage to the coating layer. This is because the penetration depth is determined by the vertical velocity component difference between the impacting particle and the coating layer, but irrelevant to the horizontal component. The total energy of the coating layer increases with the time, while the internal energy increases with the time after some peak values, which is due to energy transmission from the spherical particle to the coating layer and the stress shock waves. The energy transmission from impacting particle to coating layer increases with the increasing particle velocity, and decreases with the increasing inclined angle. The simulated impact pit morphology is qualitatively similar to the experimental observation. This work demonstrates that the SPH method is useful to analyze the impact behavior of ceramic coatings.

Inner Edge Drag by an Asynchronous Primary and Accretion Disc Structure in Close Binaries

1996 ◽  
Vol 158 ◽  
pp. 117-118
Author(s):  
G. Lanzafame ◽  
G. Belvedere ◽  
D. Molteni
Keyword(s):  
Angular Velocity ◽  
Compact Star ◽  
Magnetic Coupling ◽  
Central Star ◽  
Accretion Disc ◽  
Close Binaries ◽  
Integration Time ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Intermediate Polars

In this work a 3–D ‘Smoothed Particle Hydrodynamics’ ([1]; [4]; [5]) accretion disc is simulated where particles at its inner edge are dragged by a fast spinning compact central star, as in the case of the intermediate polars. The angular velocity of the central star is twice the orbital angular velocity ωo. This drag can be attributed mainly to viscous interaction in the dense compact star atmosphere, although magnetic coupling may also play a role.Our simulations have been performed for a system with a primary (a white dwarf) mass M1 = 1.3 M⊙, a secondary mass M2 = 2.2 M⊙, a separation between the components (centre to centre) d12 = 6.33 1011 cm and an orbital period = 1.7 d, the integration time being as long as ≃ 75 d. As in [2] and [3], we have considered quasi-polytropic structures with γ = 1.01. We adopt the term quasi-polytropic since we have in fact solved also an energy equation.

scholarly journals The evolution of large cavities and disc eccentricity in circumbinary discs

2020 ◽  
Vol 499 (3) ◽  
pp. 3362-3380
Author(s):  
Enrico Ragusa ◽  
Richard Alexander ◽  
Josh Calcino ◽  
Kieran Hirsh ◽  
Daniel J Price
Keyword(s):  
Initial Conditions ◽  
Semimajor Axis ◽  
High Mass ◽  
Dust Trapping ◽  
Low Contrast ◽  
Evolutionary Features ◽  
Cavity Structure ◽  
Particle Hydrodynamics ◽  
Long Time ◽  
Smoothed Particle

ABSTRACT We study the mutual evolution of the orbital properties of high-mass ratio, circular, co-planar binaries and their surrounding discs, using 3D Smoothed Particle Hydrodynamics simulations. We investigate the evolution of binary and disc eccentricity, cavity structure, and the formation of orbiting azimuthal overdense features in the disc. Even with circular initial conditions, all discs with mass ratios q > 0.05 develop eccentricity. We find that disc eccentricity grows abruptly after a relatively long time-scale (∼400–700 binary orbits), and is associated with a very small increase in the binary eccentricity. When disc eccentricity grows, the cavity semimajor axis reaches values $a_{\rm cav}\approx 3.5\, a_{\rm bin}$. We also find that the disc eccentricity correlates linearly with the cavity size. Viscosity and orbit crossing appear to be responsible for halting the disc eccentricity growth – eccentricity at the cavity edge in the range ecav ∼ 0.05–0.35. Our analysis shows that the current theoretical framework cannot fully explain the origin of these evolutionary features when the binary is almost circular (ebin ≲ 0.01); we speculate about alternative explanations. As previously observed, we find that the disc develops an azimuthal overdense feature in Keplerian motion at the edge of the cavity. A low-contrast overdensity still co-moves with the flow after 2000 binary orbits; such an overdensity can in principle cause significant dust trapping, with important consequences for protoplanetary disc observations.

scholarly journals On the cavity size in circumbinary discs

2020 ◽  
Vol 498 (2) ◽  
pp. 2936-2947 ◽  
Author(s):  
Kieran Hirsh ◽  
Daniel J Price ◽  
Jean-François Gonzalez ◽  
M Giulia Ubeira-Gabellini ◽  
Enrico Ragusa
Keyword(s):  
Aspect Ratio ◽  
Smoothed Particle Hydrodynamics ◽  
Surface Density ◽  
Semimajor Axis ◽  
Cavity Size ◽  
Polar Orbit ◽  
Dynamical Time ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

ABSTRACT How does the cavity size in circumbinary discs depend on disc and binary properties? We investigate by simulating disc cavities carved by binary companions using smoothed particle hydrodynamics. We find that a cavity is quickly opened on the dynamical time, while the cavity size is set on the viscous time. In agreement with previous findings, we find long-term cavity sizes of 2–5 times the binary semimajor axis, increasing with eccentricity and decreasing with disc aspect ratio. When considering binaries inclined with respect to the disc, we find three regimes: (i) discs that evolve towards a coplanar orbit have a large cavity, slightly smaller than that of an initially coplanar disc; (ii) discs that evolve towards a polar orbit by breaking have a small cavity, equal in size to that of an initially polar disc; and (iii) discs that evolve towards a polar orbit via warping have an intermediate-sized cavity. We find typical gas depletions inside the cavity of ≳2 orders of magnitude in surface density.

Giant Impacts and Debris Disks

2012 ◽  
Vol 8 (S293) ◽  
pp. 270-272
Author(s):  
H. Genda ◽  
H. Kobayashi ◽  
E. Kokubo
Keyword(s):  
High Resolution ◽  
Surface Density ◽  
Terrestrial Planet ◽  
Central Star ◽  
Infrared Excess ◽  
Excess Emission ◽  
Giant Impacts ◽  
Last Stage ◽  
Debris Disk ◽  
Impact Simulations

AbstractDuring the last stage of terrestrial planet formation, Mars-sized protoplanets often collides with each other. Our high-resolution impact simulations show that such giant impacts produce a significant amount of fragments within the terrestrial planet region. These ejected fragments form a hot debris disk around the central star. We calculated the evolution of the surface density and size distribution of the debris disk using the analytical model of collision disruption, and estimated its infrared excess emission. We found that 24 μm flux from the debris disk is higher than stellar flux throughout the giant impact stage (~ 108 years), which can explain the infrared excess recently observed around the star with the age of 107 – 108 years.

scholarly journals Migration jumps of planets in transition discs

2020 ◽  
Vol 643 ◽  
pp. A87
Author(s):  
Thomas Rometsch ◽  
Peter J. Rodenkirch ◽  
Wilhelm Kley ◽  
Cornelis P. Dullemond
Keyword(s):  
Equations Of State ◽  
Accretion Rate ◽  
Dynamical Evolution ◽  
Central Star ◽  
Dynamical Behaviour ◽  
High Mass ◽  
Outer Planet ◽  
Mass Accretion Rate ◽  
Wide Transition ◽  
Outward Migration

Context. Transition discs form a special class of protoplanetary discs that are characterised by a deficiency of disc material close to the star. In a subgroup, inner holes in these discs can stretch out to a few tens of au while there is still mass accretion onto the central star observed at the same time. Aims. We analyse the proposition that this type of wide transition disc is generated by the interaction of the disc with a system of embedded planets. Methods. We performed two-dimensional hydrodynamics simulations of a flat disc. Different equations of state were used including locally isothermal models and more realistic cases that consider viscous heating, radiative cooling, and stellar heating. Two massive planets (with masses of between three and nine Jupiter masses) were embedded in the disc and their dynamical evolution due to disc–planet interaction was followed for over 100 000 yr. The simulations account for mass accretion onto the star and planets. We included models with parameters reminiscent of the system PDS 70. To assess the observability of features in our models we performed synthetic ALMA observations. Results. For systems with a more massive inner planet, there are phases where both planets migrate outward engaged in a 2:1 mean motion resonance via the Masset-Snellgrove mechanism. In sufficiently massive discs, the resulting formation of a vortex and the interaction with it can trigger rapid outward migration of the outer planet where its distance can increase by tens of au in a few thousand years. After another few thousand years, the outer planet rapidly migrates back inwards into resonance with the inner planet. We call this emerging composite phenomenon a migration jump. Outward migration and the migration jumps are accompanied by a high mass accretion rate onto the star. The synthetic images reveal numerous substructures depending on the type of dynamical behaviour. Conclusions. Our results suggest that the outward migration of two embedded planets is a prime candidate for the explanation of the observed high stellar mass accretion rate in wide transition discs. The models for PDS 70 indicate it is not currently undergoing a migration jump but might very well be in a phase of outward migration.

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