Unseen Architectures: Revealing Low Mass Planets on Long Period Orbits

A team will find and characterize new planets around distant stars in order to understand planet formation. The team will detect low mass planets in systems similar to our own Solar System, small planets close to their stars that also have cold, more massive companions. The team will detect these low mass planets in time for follow up by the James Webb Space Telescope during its primary mission lifetime. This continuing survey may detect Earth-like planets in habitable orbits around Sun-like stars. This work will be carried out by undergraduate and masters students from a minority serving institution. In addition to research, students will prepare related Spanish language outreach content both to involve the local community and share science more widely. Students will also organize and run monthly Spanish language outreach events, with talks, planetarium shows, and telescope viewing. Long running radial velocity surveys have begun to identify large planets as far out as 10 Astronomical Units from their host stars. However, their spectroscopic sensitivity has been unable to find many of the super-Earths and sub-Neptunes that are ubiquitous in transit surveys, especially beyond 1 Astronomical Unit. The 20 cm/s nightly precision of the EXPRES spectrograph opens up precisely the parameter space that is missed from these prior surveys. Characterizing the planet architectures in this region will directly test the pebble accretion model, which predicts a lack of systems with inner super Earths and outer more massive planets. The team will use the EXPRES extreme precision radial velocity spectrograph to find low mass planets out to 4 Astronomical Units from their host stars. The program builds on 4 years of high-cadence observations with nightly spectroscopic precision of 20 cm/s. Students will actively participate in observing, both remotely and in person. A postdoc will focus on reducing photospheric noise and characterizing planet atmospheres and migration pathways. The ultra-stable instrumental profile of EXPRES allows other analyses using the time series spectra; the team will improve our understanding of photospheric activity through line profile variations and analysis of solar variability. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.