The James Webb Interferometer: Space-based interferometric detections of PDS 70 b and c at 4.8 $μ$m (2404.13032v2)

Abstract: We observed the planet-hosting system PDS 70 with the James Webb Interferometer, JWST's Aperture Masking Interferometric (AMI) mode within NIRISS. Observing with the F480M filter centered at 4.8 $\mu$m, we simultaneously fit geometrical models to the outer disk and the two known planetary companions. We re-detect the protoplanets PDS 70 b and c at an 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 SED models to these new measurements and those found in the literature. We also newly detect emission within the disk gap at an SNR of $\sim$4, at a position angle of $220^{+10}_{-15}$ degrees, and an unconstrained separation within $\sim$200 mas. Follow-up observations will be needed to determine the nature of this emission. We place a 5$\sigma$ upper limit of 208 $\pm$ 10 $\mu$Jy on the flux of the candidate PDS 70 d at 4.8 $\mu$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$\sigma$ contrast upper limit $>$7 magnitudes at separations greater than 110 mas. These are the deepest limits to date within $\sim$250 mas at 4.8 $\mu$m and the first space-based interferometric observations of this system.

• The paper re-detects protoplanets PDS 70 b and c using space-based interferometry with high SNR measurements of 14.7 and 7.0, respectively.
• It employs advanced modeling to analyze photometric data and reveals mid-IR circumplanetary disk emissions alongside a 5σ contrast limit for additional bodies.
• The study demonstrates the effectiveness of JW Interferometer techniques in exoplanet characterization, laying groundwork for improved planet formation models.

Insights into Space-based Interferometric Detections of PDS 70 b and c with the James Webb Interferometer

The reported paper involves the utilization of the James Webb Interferometer to observe the planet-hosting system PDS 70. This investigation leverages the Near Infrared Imager and Slitless Spectrograph's (NIRISS) Aperture Masking Interferometric (AMI) mode, using a 4.8 μm filter to detect the known protoplanets PDS 70 b and c. Achieving a detection signal-to-noise ratio (SNR) of 14.7 for PDS 70 b and 7.0 for PDS 70 c, this work extends our understanding of these celestial bodies through both the re-detection and new observational insights.

Key Findings and Methodology

1. Detection and Analysis: The research successfully re-detects protoplanets PDS 70 b and c and provides detailed photometric measurements. By integrating these measurements with spectral energy distribution (SED) models, the paper provides tentative evidence for mid-IR circumplanetary disk emissions around the planets.
2. Observational Geometry: Enhanced modeling was employed to understand both the positions and emissions of these protoplanets in relation to the disk gap. The introduction of a comprehensive model fitting routine allowed for the detailed analysis of emission signals from the disk and planetary companions, revealing emission within the disk gap at a SNR of approximately 4.
3. Upper Limits on Further Detection: The research places stringent constraints on the presence of additional planets within the system. At a separation greater than 110 mas, the paper reports an azimuthally averaged 5σ contrast upper limit greater than 7 magnitudes, representing the deepest limits achieved to date at 4.8 μm using space-based interferometry.

Theoretical and Practical Implications

The observations have notable implications for both theoretical models of planetary formation in protoplanetary disks and practical methodologies in space-based interferometry. By determining the photometry of both planets and inferring the presence of circumplanetary disks, the paper indirectly supports models suggesting that these features may influence early planetary formation stages. This provides a robust groundwork for understanding how similar processes might operate in other star systems.

The paper also underscores the capabilities of the James Webb Space Telescope’s NIRISS for high-angular-resolution observations, highlighting its potential in deciphering complex astronomical systems at wavelengths beyond the optical spectrum.

Speculative Future Prospects

Future investigations into PDS 70 and similar systems could refine planet formation theories, particularly those addressing disk-planet interactions. Moreover, with technological advancements in interferometry and imaging, a deeper quantification of disk characteristics and planet atmospheres could be achieved, revealing new insights into their composition and dynamics.

Subsequent observational campaigns could leverage the techniques and methodologies developed in this paper to explore other young, planet-forming systems. This could validate the current findings related to disk emissions and potentially uncover new celestial phenomena.

In conclusion, the application of space-based interferometric observations marks a significant stride in exoplanet research, enhancing our comprehension of early planetary systems' architecture and evolution. The outcomes from this paper not only provide specific insights into the PDS 70 system but also set a precedent for future exploration of star-planet formation mechanics in the wider universe.