High-resolution Spectra for a Wide Range of Habitable Zone Planets around Sun-like Stars

TL;DR

This paper provides a comprehensive database of high-resolution spectra for simulated habitable exoplanets across various surface types and host stars, aiding future observational strategies and data interpretation.

Contribution

It introduces a new database of high-resolution spectra for diverse habitable zone exoplanets, covering a wide parameter space for use in upcoming telescope observations.

Findings

Spectral feature strength varies with surface type and host star.

Overall reflectance and emission depend on surface and star characteristics.

Contrast ratios inform target prioritization for future observations.

Abstract

The search for life in the universe is currently focused on Earth-analog planets. However, we should be prepared to find a diversity of terrestrial exoplanets not only in terms of host star but also in terms of surface environment. Simulated high-resolution spectra of habitable planets covering a wide parameter space are essential in training retrieval tools, optimizing observing strategies, and interpreting upcoming observations. Ground-based extremely large telescopes like ELT, GMT, and TMT; and future space-based mission concepts like Origins, HabEx, and LUVOIR are designed to have the capability of characterizing a variety of potentially habitable worlds. Some of these telescopes will use high precision radial velocity techniques to obtain the required high-resolution spectra ($R\approx100,000$) needed to characterize potentially habitable exoplanets. Here we present a database of high-resolution (0.01 cm$^{-1}$) reflection and emission spectra for simulated exoplanets with a wide range of surfaces, receiving similar irradiation as Earth around 12 different host stars from F0 to K7. Depending on surface type and host star, we show differences in spectral feature strength as well as overall reflectance, emission, and star to planet contrast ratio of terrestrial planets in the Habitable zone of their host stars. Accounting for the wavelength-dependent interaction of the stellar flux and the surface will help identify the best targets for upcoming spectral observations in the visible and infrared. All of our spectra and model profiles are available online.