The James Webb Interferometer: Space-based Interferometric Detections of PDS 70 b and c at 4.8 μm

We observed the planet-hosting system PDS 70 with the James Webb Interferometer, JWST's aperture masking interferometric mode within NIRISS. Observing with the F480M filter centered at 4.8 μ m, we simultaneously fit geometrical models to the outer disk and the two known planetary companions. We redetect the protoplanets PDS 70 b and c at a signal-to-noise ratio (SNR) of 14.7 and 7.0, respectively. Our photometry of both PDS 70 b and c provides tentative evidence of mid-IR circumplanetary disk emission through fitting spectral energy distribution models to these new measurements and those found in the literature. We also newly detect emission within the disk gap at an SNR of ~4, a position angle of $22{0}_{-15}^{+10}$ °, and an unconstrained separation within ~200 mas. Follow-up observations will be needed to determine the nature of this emission. We place a 5 σ upper limit of 208 ± 10 μ Jy on the flux of the candidate PDS 70 d at 4.8 μ m, which indicates that if the previously observed emission at shorter wavelengths is due to a planet, this putative planet has a different atmospheric composition than PDS 70 b or c. Finally, we place upper limits on emission from any additional planets in the disk gap. We find an azimuthally averaged 5 σ contrast upper limit >7 mag at separations greater than 110 mas. These are the deepest limits to date within ~250 mas at 4.8 μ m and the first space-based interferometric observations of this system.