A Search for Collisions and Planet-Disk Interactions in the Beta Pictoris Disk with 26 Years of High Precision HST/STIS Imaging

TL;DR

This study uses 26 years of high-precision HST/STIS imaging to search for collisions and planet-disk interactions in the Beta Pictoris debris disk, finding no recent collision evidence but noting a possible brightness increase.

Contribution

It provides the longest temporal baseline for debris disk observation, combining multi-epoch data to constrain collision activity and planet-disk interactions with high sensitivity.

Findings

No localized brightness changes indicative of recent collisions.

Tentative brightening of the southeast side over a decade.

Sensitivity to debris down to Ceres-mass per progenitor.

Abstract

Beta Pictoris (Beta Pic)'s well-studied debris disk and two known giant planets, in combination with the stability of HST/STIS (and now also JWST), offers a unique opportunity to test planet-disk interaction models and to observe recent planetesimal collisions. We present HST/STIS coronagraphic imaging from two new epochs of data taken between 2021 and 2023, complementing earlier data taken in 1997 and 2012. This dataset enables the longest baseline and highest precision temporal comparison of any debris disk to date, with sensitivity to temporal surface brightness variations of sub-percentage levels in the midplane of the disk. While no localized surface brightness changes are detected, which would be indicative of a recent planetesimal collision, there is a tentative brightening of the SE side of the disk over the past decade. We link the constraints on surface brightness variations to dynamical models of the planetary system's evolution and to the collisional history of planetesimals. Using a coupled collisional model and injection/recovery framework, we estimate sensitivity to expanding collisional debris down to a Ceres-mass per progenitor in the most sensitive regions of the disk midplane. These results demonstrate the capabilities of long-baseline, temporal studies with HST (and also soon with JWST) for constraining the physical processes occurring within debris disks.