James Webb Space Telescope Feed Post

Arxiv: Imaging of the Vega Debris System using JWST/MIRI Published: 10/31/2024 7:03:19 AM Updated: 10/31/2024 7:03:19 AM

Paper abstract: We present images of the Vega planetary debris disk obtained at 15.5, 23, and25.5 microns with the Mid-Infrared Instrument (MIRI) on JWST. The debris systemis remarkably symmetric and smooth, and centered accurately on the star. Thereis a broad Kuiper-belt-analog ring at 80 to 170 au that coincides with theplanetesimal belt detected with ALMA at 1.34 mm. The interior of the broad beltis filled with warm debris that shines most efficiently at mid-infrared alongwith a shallow flux dip/gap at 60 au from the star. These qualitativecharacteristics argue against any Saturn-mass planets orbiting the star outsideof about 10 au assuming the unseen planet would be embedded in the very broadplanetesimal disk from a few to hundred au. We find that the distribution ofdust detected interior to the broad outer belt is consistent with grains beingdragged inward by the Poynting-Robertson effect. Tighter constraints can bederived for planets in specific locations, for example any planet shepherdingthe inner edge of the outer belt is likely to be less than 6 Earth masses. Thedisk surface brightness profile along with the available infrared photometrysuggest a disk inner edge near 3-5 au, disconnected from the sub-au region thatgives rise to the hot near-infrared excess. The gap between the hot, sub-auzone and the inner edge of the warm debris might be shepherded by a modestmass, Neptune-size planet.