Extension of ATLAST/LUVOIR's Capabilities to 5 Microns, or Beyond

TL;DR

Extending the ATLAST/LUVOIR space telescope's wavelength range to at least 5 microns enhances its capabilities for exoplanet atmosphere studies and broad astrophysical research, with a proposed fiber-fed spectrometer design.

Contribution

This paper demonstrates the technical feasibility and scientific benefits of extending ATLAST/LUVOIR's infrared capabilities beyond 2 microns, including a conceptual spectrometer design.

Findings

Extension to 5 microns is technically feasible.

Enhanced exoplanet atmosphere analysis capabilities.

Broader astrophysical research potential.

Abstract

ATLAST is a particular realization of LUVOIR, the Large Ultraviolet Optical Infrared telescope, a ~10 m diameter space telescope being defined for consideration in the 2020 Decadal Review of astronomy and astrophysics. ATLAST/LUVOIR is generally thought of as an ambient temperature (~300 K) system, and little consideration has been given to using it at infrared wavelengths longward of ~2 {\mu}m. We assess the scientific and technical benefits of operating such a telescope further into the infrared, with particular emphasis on the study of exoplanets, which is a major science theme for ATLAST/LUVOIR. For the study of exoplanet atmospheres, the capability to work at least out to 5.0 {\mu}m is highly desirable. Such an extension of the long wavelength limit of ATLAST would greatly increase its capabilities for studies of exoplanet atmospheres and provide powerful capabilities for the study of a wide range of astrophysical questions. We present a concept for a fiber-fed grating spectrometer which would enable R = 200 spectroscopy on ATLAST with minimal impact on the other focal planet instruments. We conclude that it is technically feasible and highly desirable scientifically to extend the wavelength range of ATLAST to at least 5 {\mu}m.