James Webb Space Telescope Feed Post

JWST-TST High Contrast: Asymmetries, dust populations and hints of a collision in the Beta Pictoris disk with NIRCam and MIRI

An example illustrating the components of the MCRDI model for the F335M data. Left: the reduced MCRDI image. Middle left: the best-fit PSF-convolved disk model. Middle right: the composite disk and planet model. Right: the final residual map for this model. The field of view is chosen to show the model within approximately the r<2?.''?34 optimization region used for MCRDI. As in Fig. 1, the images were rotated by 60.9° to align the main disk with the horizontal axis. Abstract: We present the first JWST MIRI and NIRCam observations of the prominent debris disk around Beta Pictoris. Coronagraphic observations in 8 filters spanning from 1.8 to 23~µm provide an unprecedentedly clear view of the disk at these wavelengths. The objectives of the observing program were to investigate the dust composition and distribution, and to investigate the presence of planets in the system. In this paper, we focus on the disk components, providing surface brightness measurements for all images and a detailed investigation of the asymmetries observed. A companion paper by Kammerer et al. will focus on the planets in this system using the same data. We report for the first time the presence of an extended secondary disk in thermal emission, with a curved extension bent away from the plane of the disk. This feature, which we refer to as the "cat's tail", seems to be connected with the previously reported CO clump, mid-infrared asymmetry detected in the southwest side, and the warp observed in scattered light. We present a model of this secondary disk sporadically producing dust that broadly reproduces the morphology, flux, and color of the cat's tail, as well as other features observed in the disk, and suggests the secondary disk is composed largely of porous, organic refractory dust grains.