High-contrast imaging is a powerful tool to probe the atmospheres and orbital architectures of long-period planets. The development of extreme adaptive optics instruments, novel coronagraph designs,…

This federal contract award to the University of Texas at Austin (UT Austin) is for a $568,757 grant to develop methods for directly imaging long-period exoplanets around nearby stars. The goal is to identify promising target stars with astrometric evidence of long-period companions, then follow up with high-contrast imaging to search for new planets. This work aligns with NASA's Exoplanet Research Program and aims to identify optimal targets for future observations with the James Webb Space Telescope. UT Austin is the prime contractor, leveraging its expertise in astronomy, adaptive optics, and data analysis. The contract does not have a set-aside designation. The award is funded by the National Aeronautics and Space Administration (NASA).

High-contrast imaging is a powerful tool to probe the atmospheres and orbital architectures of long-period planets. The development of extreme adaptive optics instruments, novel coronagraph designs, and increasingly sophisticated post-processing methods has facilitated the discovery of about a dozen planets with separations within 100 AU via direct imaging. Despite the scientific importance and long-term potential of this planet-finding technique, the scarcity of giant planets at large separations has emerged as the single largest barrier that has limited the scientific growth of this field over the past decade. The goal of this program is to dramatically improve these outcomes and deliver discoveries of new planets for existing telescopes and future facilities like jwst. Our approach is to identify promising targets based on their astrometric reflex accelerations from hipparcos and gaia DR2, which span a 24-year baseline. By focusing on targets with astrometric evidence of long-period planets, this program will facilitate the first significant transition from blind direct imaging surveys to dynamically informed targets, mitigating the impact of low planet occurrence rates at wide separations that have hindered previous campaigns. Our program consists of three phases: (1) identify young STARS with low-amplitude astrometric accelerations, (2) conduct follow up high-resolution imaging and spectroscopy to remove false positives caused by stellar, brown dwarf, and white dwarf companions, and (3) carry out a focused high-contrast imaging survey of the most promising young STARS that have accelerations consistent with long-period giant planets. We will make use of the new hipparcos-gaia catalog of accelerations (hgca), which is the largest and most sensitive catalog of accelerating nearby bright STARS to date. To demonstrate the utility and reliability of the hgca catalog, our team recently used the astrometric accelerations of host STARS with known brown dwarf, white dwarf, and giant planet companions to constrain their orbits and dynamical masses. This strategy has opened an unprecedented opportunity to find young STARS with dynamical evidence of low-mass companions at separations accessible to the current generation of high-contrast imagers. Our program is well-matched with the primary goal of NASA's exoplanet research program to discover and characterize planetary systems. In particular, these observations will be used to identify optimal targets with strategic relevance for follow-up high-contrast near- and mid-infrared imaging using jwst and ground-based facilities. Since jwst is unlikely to carry out a substantial direct imaging search for new planets during its primary mission, new discoveries and single young accelerating STARS that emerge from our program will help make optimal use of this facility in the near future.