Dr. Aarynn Carter (Space Telescope Science Institute)

The high-contrast imaging capabilities of JWST have dramatically expanded our ability to directly detect exoplanets. With its exquisite stability and infrared sensitivity, JWST has enabled the detection and characterization of the coldest known exoplanets to date, such as Eps Indi A b and 14 Her c at just 300 K, and the discovery of the lowest mass imaged planet to date, TWA 7b, with a mass close to our own Saturn. While striking results in isolation, their impact is better measured in terms of the broader questions we can now begin to answer: “How common are Saturn mass planets at wide separations?”, and “What are the dominant features and diversity across cold gas giant atmospheres?”. In this talk, I will give context to the growing achievements of JWST high-contrast imaging, centered on emerging results from three combined JWST NIRCam 2.0+4.4 micron imaging surveys of nearby associations and young moving groups, totaling ~170 stars of spectral type A through M (GO4050, GO5835, SURVEY6005). Our surveys reach Saturn mass sensitivities and below, and preliminary vetting efforts have identified over 2000 individual sources for further investigation, of which we have now filtered into a sub-sample of high-priority exoplanet candidates. While further observations will be necessary to truly validate their planetary natures, we are still able to estimate preliminary statistical constraints on the sub-Jupiter exoplanet population. Our observations have also revealed several debris disk detections, further demonstrating JWST NIRCam’s unique capabilities for scattered light disk imaging. Following further verification of our candidates, we aim to refine our occurrence rates, and define a robust sample of cold, low-mass exoplanets amenable for further characterization with JWST or other upcoming telescopes. These exoplanets will be the closest known analogues to our own Saturn and Jupiter, and future population-level characterization studies may lead to deeper insights into the formation and evolution of gas giants, and planetary systems as a whole.