Seminario de Astrofísica: “Simulation of the Impact of Jupiter-Type Rogue Planets on Circumstellar Disks”

Seminario de Astrofísica en el IFIS. Este martes 13 de mayo, Patricio Messen, estudiante del Magíster en Física de la Pontificia Universidad Católica de Valparaíso, presentará “Simulation of the Impact of Jupiter-Type Rogue Planets on Circumstellar Disks” a las 14:30 horas en la Sala 208 del Instituto de Física, Campus Curauma.

Compartimos el abstract de la presentación:

Circumstellar disks are structures of gas and dust that surround young stars during the early stages of their evolution. These disks are thought to be the sites of planet formation, and observations have revealed complex substructures with unclear origins, such as prominent spirals, low-density rings, and high-density regions where material accumulates.

In this work, we perform two-dimensional hydrodynamic simulations using the FARGO3D code, where we perturb a circumstellar disk with a Jupiter mass planet undergoing a coplanar flyby. We compare cases where the planet follows a prograde or retrograde trajectory. Simulations are carried out using two different equations of state: isothermal and adiabatic. The disk morphology varies significantly depending on the planet’s trajectory, and in all models, spiral-shaped density waves are generated and propagate throughout the disk.

In the retrograde case, two relatively close spiral arms form, while in the prograde scenario, two nearly symmetric spirals appear with respect to the central object. Under the isothermal condition, the spirals exhibit a more compact and well-defined structure compared to the adiabatic case, due to the absence of local temperature variations that would affect gas pressure. When local temperature variations are considered in the adiabatic models, we find that in the prograde case, the region where the spiral arms intersect experiences a significant temperature increase compared to the retrograde case.

To assess the observable differences between these scenarios, we adopt an approximation assuming dust perfectly coupled to the gas, and generate a synthetic spectral energy distribution (SED). This reveals that the temperature peak leads to an increase in the disk’s emitted flux. By evaluating viscous dissipation terms, we find that these events produce changes in bolometric luminosity below 1%, with prograde cases yielding the largest variation.

All simulated cases produce a low-density ring (gap) at approximately 8 AU from the central object. Uniquely in the prograde case with an adiabatic equation of state, a high-density ring forms just outside the gap, potentially acting as a dust trap and possibly triggering planetesimal formation. Finally, we perform a purely morphological comparison with Elias 2-27, a system that exhibits spiral arms with features resembling those of our simulated disks in the prograde scenario, which may provide insight into the origin of Elias 2-27’s observed morphology.

Extendemos la invitación a la comunidad a participar de este seminario que busca aportar al entendimiento de los procesos de formación planetaria.

Seminario de Astrofísica: “Bias Function and the Cosmic-Web connection”

Seminario de Astrofísica en el IFIS. Este martes 6 de mayo, Constanza Soto estudiante de Doctorado de Ciencias Físicas de la PUCV y UTFSM, presenta “Bias Function and the Cosmic-Web connection” desde las 14:30 en la Sala 208 del Instituto de Física PUCV.

Revisa el abstract de la presentación:

The spatial distribution of galaxies and dark matter haloes is not random and carries crucial information about the evolution of the universe. When referring to large-scale structure (LSS), we describe an inhomogeneous universe whose nature is studied through the evolution of perturbations in the density field. On larger scales, the evolution of these fluctuations, driven by the gravitational interaction of matter, gives rise to the formation of complex structures such as nodes, filaments, voids, and walls, collectively known as the cosmic web. Following this idea, the relation between the distribution of galaxies or dark matter haloes and the underlying matter density field is referred to as bias. The primary dependence of halo clustering is on halo mass, such that more massive haloes are more clustered than their less massive counterparts. However, secondary properties, at fixed halo mass, also influence clustering, leading to the so-called secondary bias. In this study, using the TNG300 hydrodynamical simulation, we employed an individual halo bias estimator, leveraging its advantages over traditional methods. With this estimator, we constructed the halo bias function, defined as the relation between the average individual bias per halo mass bin. By analyzing the halo bias function across different environments, we found that the trend varies for each environment, indicating that haloes located in the outskirts of nodes are highly clustered, in contrast to haloes in voids and walls. Similarly, linking to galaxy properties, we observed that haloes hosting red galaxies are more clustered, across all environments, than those hosting blue galaxies. Additionally, at low masses (log10(Mhost) < 12.5 h−1M⊙), red galaxies are significantly influenced by nearby massive haloes (log10(Mhost) > 13.5h−1M⊙)) within a radius of 5 h−1Mpc.