arXiv subjects

Nerea Gurrutxaga

Publications and source records attributed to Nerea Gurrutxaga.

5 recordsLinked to original sources

arXiv2026

Complex gas flows in magnetized protoplanetary disks promote the formation of dust traps at low fragmentation velocities

Non-ideal magnetohydrodynamic simulations of protoplanetary disks show a plethora of complex gas structures, including winds, rings, and gaps. These affect dust transport and help form dust traps, which are essential for planetesimal formation. Although studies have explored the evolution of dust in such systems, they have done so either in 1D or without dust coagulation, and the effect of such systems on dust growth is still an active area of research. This work aims to investigate the effect of a complex gas flow architecture on global dust evolution, including dust growth and transport. We examine the timescales of different processes impacting dust evolution and discuss prospects of forming planetesimals. We post-process gas velocity output from a 2D non-ideal magnetohydrodynamic simulation using a 2D (r-z) Monte Carlo dust coagulation code to perform global simulations of dust growth and evolution. We perform three runs, one with a typical steady-state disk and two with the gas velocity from the MHD simulation, where we vary the fragmentation velocity. Our results show that the advection of small particles by the gas due to strong gas velocities can play an important role in setting the dust size distributions around protoplanetary disks. The gas flow structure has a transition region, and this region acts as a location of a dust pile-up, increasing the pebble-to-gas ratio by a factor of 2.5 when compared to the steady state disk. Lowering the fragmentation velocity improves the stability of the pile-up, but the pebble concentration is not as high. This scenario acts as a way to form a dust trap in a disk without a pressure bump. We discuss the possibilities for planetesimal formation in such a trap.

astro-ph.EP↗

arXiv2026

A Monte Carlo method for tracking dust properties during coagulation in protoplanetary disks

Dust growth is a crucial step in planet formation, and the efficiency of this process is controlled by the physical and chemical properties of the dust grains. Monte Carlo-based methods are commonly used to follow the collisional evolution of dust while tracking their properties. However, current Monte Carlo methods in planet formation do not strictly conserve the global inventory of dust properties across the protoplanetary disk, causing fluctuations that can grow over time and affect predictions of dust evolution. Here we present a coagulation algorithm that ensures the global conservation of dust properties while resolving the spatial evolution of dust. The method is validated against analytical solutions for standard coagulation kernels and benchmarked in a two-dimensional disk. We show that the method reproduces standard results, resolves the full dust population, and improves the resolution of the small-grain regime compared to other Monte Carlo methods for modeling global dust evolution. Finally, using a test case that includes sublimation and condensation of water interacting with silicates, we demonstrate strict conservation of each component's mass during coagulation, establishing the method as a valuable tool for tracking dust properties in protoplanetary disks.

astro-ph.EP↗

arXiv2026

Carbonaceous Chondrites provide evidence for late-stage planetesimal formation in a pressure bump

Carbonaceous chondrites are samples from planetesimals that formed 2-4 million years after solar system formation began. They consist of distinct dust components formed at different times and locations in the accretion disk and whose abundances in carbonaceous chondrites vary over planetesimal formation time. The mechanism that led to this time-varied accretion is not understood, but is critical for understanding late-stage planetesimal formation. Using a two-dimensional Monte Carlo simulation of dust evolution, we show that differences in dust filtering and delivery rates of distinct dust components to a planet-induced pressure bump in the disk reproduce the observed compositions and formation ages of the carbonaceous chondrites. This implies that carbonaceous chondrites likely formed in a single, long-lived dust trap, most likely outside of Jupiter's orbit. Because differentiated meteorites, which sample an earlier generation of planetesimals, exhibit similar isotopic variability as the chondrites, they likely have also formed in dust traps, implying these structures were the dominant site for planetesimal formation in the solar system.

astro-ph.EP↗

arXiv2025

mcdust: A 2D Monte Carlo code for dust coagulation in protoplanetary disks

mcdust is a parallel simulation code for dust evolution in protoplanetary disks. The code is written in FORTRAN90 and parallelised with OpenMP. The code models dust collisional evolution and transport in the vertical and radial directions. The currently included collisional outcomes are dust growth by sticking, fragmentation of dust particles and erosion, where a small particle chips a portion of the large particle. We employ a representative particle approach to track a limited number of particles instead of tracking every particle, saving computational time. We have a static power-law gas disk with temperature assumed to be vertically isothermal. Dust coagulation depends on the local gas properties, and therefore, we bin particles into grids and perform collisions. We make use of an adaptive grid approach where we make sure that each cell has an equal number of representative particles. This guarantees that there are always sufficient particles to resolve the physics of collisions. The code resolves dust coagulation in 2D(r-z). To access the documentation of the code, see https://mcdust.readthedocs.io/ .

astro-ph.IM↗

arXiv2024

Formation of wide-orbit giant planets in protoplanetary disks with a decreasing pebble flux

The presence of distant protoplanets may explain the observed gaps in the dust emission of protoplanetary disks. Here, we derive a novel analytical model to describe the temporal decay of the pebble flux through a protoplanetary disk as the result of radial drift. This has allowed us to investigate the growth and migration of distant protoplanets throughout the lifespan of the disk. We find that Moon-mass protoplanets that formed early on can grow to their pebble isolation mass, between approximately $20$ and $80\,M_{\oplus}$, within less than $1\,\mathrm{Myr,}$ in the $20$ to $80\,\mathrm{AU}$ region around solar-like stars. The subsequent fast migration in the early stages of gas accretion, after pebble accretion ends, transports these giant planets into their final orbits at $<\,$$10\,\mathrm{AU}$. However, our pebble decay model allows us to include a new pathway that may trigger the transition from pebble accretion to gas accretion after the pebble flux has decayed substantially. With this pebble decay pathway, we show that it is also possible to form gas giants beyond $10\,\mathrm{AU}$. The occurrence of these wide-orbit gas giants should be relatively low, since their core must attain sufficient mass to accrete gas before the pebble flux decays, while avoiding excessive migration. Since these gas giants do not reach the pebble isolation mass, their heavy element content is typically less than $10\,M_{\oplus}$. Our results imply that the observed gaps in protoplanetary disks could be caused by distant protoplanets that reached the pebble isolation mass and then migrated, while gas giants in wide orbits, such as PDS 70 b and c, accreted their gas after the decay in the pebble flux.

astro-ph.EP↗