Reflected spectroscopy of small exoplanets II: characterization of terrestrial exoplanets

Abstract

A space telescope capable of high-contrast imaging has been recognized as the avenue toward finding terrestrial planets around nearby Sun-like stars and characterizing their potential habitability. It is thus essential to quantify the capability of reflected light spectroscopy obtained through direct imaging for terrestrial exoplanets, and existing work focused on planetary analogs of modern Earth. Here we go beyond Earth analogs and use a Bayesian retrieval algorithm, ExoReL${}^{\Re }$, to determine what we could learn about terrestrial exoplanets from their reflected light spectra. Recognizing the potential diversity of terrestrial exoplanets, our focus is to distinguish atmospheric scenarios without any a priori knowledge of the dominant gas. We find that, while a moderate-resolution spectrum in the optical band ($0.4-1.0\mu$m) may sufficiently characterize a modern Earth analog, it would likely result in incorrect interpretation for planets similar to Archean Earth or having CO${}_2$-dominated atmospheres. Including observations in the near-infrared bands ($1.0-1.8\mu$m) can prevent this error, determine the main component (N${}_2$, O${}_2$, or CO${}_2$), and quantify trace gases (H${}_2$O, O${}_3$, and CH${}_4$) of the atmosphere. These results are useful to define the science requirements and design the wavelength bandwidth and observation plans of exoplanet direct imaging missions in the future.

arXiv comment17 pages, 11 figures, 6 tables, accepted for publication in AJ

References in corpus (26)

• Growth Model Interpretation of Planet Size Distribution
• Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life
• Exoplanet Biosignatures: Understanding Oxygen as a Biosignature in the Context of Its Environment
• Photochemistry in Terrestrial Exoplanet Atmospheres I: Photochemistry Model and Benchmark Cases
• Spectral Evolution of an Earth-Like Planet
• Discovery and Characterization of Transiting SuperEarths Using an All-Sky Transit Survey and Follow-up by the James Webb Space Telescope
• Abiotic oxygen-dominated atmospheres on terrestrial habitable zone planets
• Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets
• Abiotic Ozone and Oxygen in Atmospheres Similar to Prebiotic Earth
• Water loss from terrestrial planets with CO2-rich atmospheres
• Photochemistry in Terrestrial Exoplanet Atmospheres III: Photochemistry and Thermochemistry in Thick Atmospheres on Super Earths and Mini Neptunes
• Venusian Habitable Climate Scenarios: Modeling Venus through time and applications to slowly rotating Venus-Like Exoplanets
• Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: A TRAPPIST-1e case study
• Day-night cloud asymmetry prevents early oceans on Venus but not on Earth
• Theoretical Spectra of Terrestrial Exoplanet Surfaces
• Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs
• Characterizing Earth Analogs in Reflected Light: Atmospheric Retrieval Studies for Future Space Telescopes
• Primary and secondary eclipse spectroscopy with JWST: exploring the exoplanet parameter space
• Unveiling shrouded oceans on temperate sub-Neptunes via transit signatures of solubility equilibria vs. gas thermochemistry
• Detectability of Molecular Signatures on TRAPPIST-1e through Transmission Spectroscopy Simulated for Future Space-Based Observatories
• Characterizing Atmospheres of Transiting Earth-like Exoplanets Orbiting M Dwarfs with James Webb Space Telescope
• ExoReL${}^{\Re }$: A Bayesian Inverse Retrieval Framework For Exoplanetary Reflected Light Spectra
• Information in the Reflected Light Spectra of Widely Separated Giant Exoplanets
• Directly imaged exoplanets in reflected starlight. The importance of knowing the planet radius
• Multi-orbital-phase and multi-band characterization of exoplanetary atmospheres with reflected light spectra
• Optical Verification Experiments of Sub-scale Starshades

Cited by in corpus (13)

• LHS 1140 b is a potentially habitable water world
• Super-Earths and Earth-like Exoplanets
• Implicit electric field Conjugation: Data-driven focal plane control
• Large Interferometer For Exoplanets (LIFE): XIII. The Value of Combining Thermal Emission and Reflected Light for the Characterization of Earth Twins
• In Search of the Edge: A Bayesian Exploration of the Detectability of Red Edges in Exoplanet Reflection Spectra
• Reflected spectroscopy of small exoplanets III: probing the UV band to measure biosignature gasses
• Constraining Background N2 Inventories on Directly Imaged Terrestrial Exoplanets to Rule Out O2 False Positives
• HWO Yield Sensitivities in the NIR and NUV
• Grid-Based Atmospheric Retrievals for Reflected-Light Spectra of Exoplanets using PSGnest
• The bright side of the light curve: a general photometric model of non-transiting exorings
• Retrievals Applied To A Decision Tree Framework Can Characterize Earth-like Exoplanet Analogs
• Influence of Orbit and Mass Constraints on Reflected Light Characterization of Directly Imaged Rocky Exoplanets
• Retrieving the Red Edge on Earth-like Planets with Heterogeneous Clouds and Surfaces