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Arxiv: The James Webb Interferometer: Space-based interferometric detections of PDS 70 b and c at 4.8 μm Published: 4/19/2024 8:45:34 PM Updated: 4/19/2024 8:45:34 PM

Paper abstract: We observed the planet-hosting system PDS 70 with the James WebbInterferometer, JWST's Aperture Masking Interferometric (AMI) mode withinNIRISS. Observing with the F480M filter centered at 4.8 \mum, wesimultaneously fit a geometric model to the outer disk and the two knownplanetary companions. We re-detect the protoplanets PDS 70 b and c at an SNR of21 and 11, respectively. Our photometry of both PDS 70 b and c provide evidencefor circumplanetary disk emission through fitting SED models to these newmeasurements and those found in the literature. We also newly detect emissionwithin the disk gap at an SNR of ~4, at a position angle of207^{+11}_{-10} degrees, and an unconstrained separation within ~200mas. Follow-up observations will be needed to determine the nature of thisemission. We place a 5\sigma upper limit of \Deltamag = 7.56 on thecontrast of the candidate PDS 70 d at 4.8 \mum, which indicates that if thepreviously observed emission at shorter wavelengths is due to a planet, thisputative planet has a different atmospheric composition than PDS 70 b or c.Finally, we place upper limits on emission from any additional planets in thedisk gap. We find an azimuthally averaged 5\sigma upper limit of \Deltamag~ 7.5 at separations greater than 125 mas. These are the deepest limitsto date within ~250 mas at 4.8 \mum and the first space-basedinterferometric observations of this system.