GRAVITY+ Non-Detection Rules Out Third Protoplanet Candidate in PDS 70

New interferometric observations with the upgraded GRAVITY+ instrument on the Very Large Telescope Interferometer targeted the PDS 70 system in 2024-2025. The team achieved 2-3 milliarcsecond resolution at K-band, sufficient to separate the candidate from both the star and the known outer protoplanets b and c. No signal was recovered at the expected location or brightness reported in earlier SPHERE and ALMA data, directly contradicting a planetary interpretation. The result aligns with the low occurrence of confirmed protoplanets and the known tendency of disk substructures to mimic point sources. Prior single-telescope imaging lacked the baseline coverage to distinguish Keplerian orbital motion from co-rotating disk features; GRAVITY+ baselines provide that discrimination in a single epoch. This strengthens the case that only two planets are confirmed in the system. Context from the original PDS 70 b and c detections (Keppler et al. 2018, A&A; Haffert et al. 2019, Nature Astronomy) shows both planets were recovered across multiple facilities and wavelengths. The inner candidate lacked such multi-epoch confirmation. Future GRAVITY+ monitoring at 6-12 month intervals can test whether any residual signal exhibits orbital motion or remains fixed relative to disk features. The non-detection demonstrates that high-angular-resolution interferometry is now essential for validating protoplanet candidates, reducing false positives that have plagued scattered-light and submillimeter surveys.