Confirm the existence of candidate planet HR 8799 f

Confirm the existence of candidate planet HR 8799 f through follow-up multi-filter JWST/NIRISS Aperture Masking Interferometry observations and common-proper-motion measurements.

Background

HR 8799 f is detected at only slightly above the 3-sigma contrast curve in a single F380M observation, so the paper characterizes it as a tentative detection. The candidate's existence requires independent confirmation through additional observations, particularly observations in multiple filters and at later epochs.

The authors emphasize that a corresponding source was not identified in a prior deep L'-band search, creating tension that must be resolved before the candidate can be accepted as a fifth planet. Confirmation would establish HR 8799 as a directly imaged five-planet system.