Planetary Embryo Collisions and the Wiggly Nature of Extreme Debris Disks

TL;DR

This study uses numerical simulations to explore the conditions under which extreme debris disks form from planetary collisions, revealing anisotropic vapor release and impact parameters affecting observability.

Contribution

It introduces a multi-stage simulation approach to analyze impact-generated vapor and dust distribution, highlighting the anisotropic nature of vapor release and its observational implications.

Findings

Impacts release vapor anisotropically, not isotropically.

Dust distribution depends on impact angle and mass ratio.

Observable vapor disks exist only in a narrow semi-major axis range.

Abstract

In this paper, we present results from a multi-stage numerical campaign to begin to explain and determine why extreme debris disk detections are rare, what types of impacts will result in extreme debris disks and what we can learn about the parameters of the collision from the extreme debris disks. 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 semi-major axis where a vapour generated disk 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.