arXiv subjects

Vitaliy Grigoryev

Publications and source records attributed to Vitaliy Grigoryev.

3 recordsLinked to original sources

arXiv2026

Simulation of a protoplanetary disk accretion activity due to a collision with a gas stream

The consequences of a protoplanetary disk collision with a gas stream are being studied using three-dimensional numerical gas-dynamic simulation. The influence of orbital parameters and the stream mass on the accretion activity of the star is examined. It is shown that the orbital inclination and the initial mass of the infalling material are the most influential parameters in determining the accretion rate. The obtained accretion rate dependencies are compared with actual observational data for two FU~Ori type stars. It turns out that not only is the maximum accretion rate consistent with observational estimates, but the behavior of the accretion rate over time is very similar to available long-term light curves.

astro-ph.SR↗

arXiv2025

Simulation of images of protoplanetary disks after collision with free-floating planets

Observational manifestations of disturbances in a protoplanetary disk caused by a collision with a massive planet are studied. It is assumed that the planet moves along a parabolic trajectory that intersects the disk plane near the star. Gas-dynamic simulation is performed using the finite volume method on a long time scale. On its basis, images of the disk observed from the pole and edge-on are constructed in the infrared and submillimeter ranges. A wide range of planet orbit parameters is considered. The approach of the planet was considered both prograde and retrograde with the respect to the disk rotation. Calculations have shown that in the images of the disk seen pole-on, two spiral arms can be observed in case of the prograde fall, and one with retrograde case. In the case of observations of a disk whose plane is inclined at a small angle to the line of sight, distortions of the disk plane can be noticeable. In addition, a gas tail is extended from the disk in the direction of the planet's motion, which can also be identified in observations.

astro-ph.EP↗

arXiv2025

Simulation of the Free Fall of a Gas Stream on a Protoplanetary Disk

The problem of the formation of exoplanets in inclined orbits relative to the equatorial plane of the parent star or the main plane of the protoplanetary disk can be solved by introducing a smaller inclined disk. However, the question of the nature of such an internal disk remains open. In the paper, we successfully tested the hypothesis about the formation of an inclined inner disk in a protoplanetary disk near a T Tau type star as a result of a gas stream falling on it. To test the hypothesis, three-dimensional gas-dynamic calculations were performed taking into account viscosity and thermal conductivity using the PLUTO package. In the course of the analysis of calculations, it was shown that a single intersection of the matter stream with the plane of the disk cannot ensure the formation of an inclined disk near the star, while a double intersection can. In addition, in the case of a retrograde fall of matter, the angle of inclination of the resulting inner disk is significantly greater. An analysis of the observational manifestations of this event was also carried out: the potential change in the brightness of the star, the distribution of optical thickness in angles, the evolution of the accretion rate. It is shown that the decrease in brightness can reach up to $5^m$, taking into account scattered light, and such a decrease in brightness will last several decades. In addition, a sharp increase in the accretion rate by two orders of magnitude could potentially trigger an FU Ori-like outburst.

astro-ph.SR↗