CAREER: Searching For Biosignatures in Exoplanet Atmospheres

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). One of the key science objectives for coming generations of astronomers will be the search for signs of life (biosignatures) on other worlds. The two US-based ELTs and the US ELT Key Science Programs will ensure the US astronomy community's involvement in searching for biosignatures in the coming decade. However, even when the ELTs are constructed, several technological hurdles need to be overcome because the community is still orders of magnitude away from directly imaging habitable planets in terms of angular separation and starlight suppression. This program will develop a novel instrument concept that will address these problems: a dual-aperture fiber nuller. The proof-of-concept instrument developed will eventually be mounted to the Large Binocular Telescope (LBT) as a pathfinder instrument for future instrument in the US ELT program. Outreach work will include a series of events at the Center of Science and Industry (COSI) and OSU to celebrate exoplanet discoveries and the resulting Nobel Prize in 2019. The events will include an exoplanet-themed After Dark Night, public lectures featuring Nobel Prize winners, a newly-developed planetarium show, and an exoplanet exhibition. This material will be brought to students in rural Ohio. This laboratory demonstration will: (1) help to better understand the error budget in system throughput and identify key areas for improvement; (2) compare with other leading concepts for direct spectroscopy with ELTs; and (3) develop a testbed that sets the stage for high-contrast instruments for ELTs. One outcome of this design reference study is to realistically estimate a timescale for deployment of the testbed instrument on the LBT. The new instrument can be a stepping stone to address technological hurdles to the search for biosignatures with ELTs such as coronagraphy at sub lambda/D resolution and diffraction-limited echelle spectroscopy. In parallel, the team will develop a spectral modeling framework to address challenges in inferring properties of planet atmospheres: (1) benchmarking performance against ground truth; (2) applying the framework to directly-imaged exoplanets; (3) dealing with data sets that vary in spectral resolution (10R100,000) and wavelength coverage; and (4) extending from gas giant planets to small rocky planets.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.