The Venus Benchmark: Resolving Degeneracies in Terrestrial Exoplanet Spectra with DAVINCI
Abstract
The characterization of terrestrial exoplanets with thick, CO2-dominated atmospheres via transmission and emission spectroscopy is limited by degeneracies between atmospheric composition, cloud structure, and surface conditions. These degeneracies are particularly acute for planets in or near the Venus Zone, where sulfuric acid aerosol layers and deep-atmosphere opacity render the lower atmosphere and surface spectroscopically inaccessible via many optical/IR wavelengths. Venus provides the only accessible analog to such worlds, yet current knowledge of its full atmospheric profile relies on decades-old in situ data with known limitations. Here we demonstrate that the forthcoming DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) mission will provide the comprehensive, high-fidelity atmospheric profile data necessary to resolve many of these degeneracies. We quantify how atmospheric profile uncertainties translate into uncertainties in modeled transmission and thermal emission spectra of CO2-dominated terrestrial worlds, and show that the spread in the modeled Venus benchmark spectrum arising from current atmospheric profile uncertainties will decrease by factors of ∼4--5 for transmission and ∼5--15× for thermal emission after DAVINCI, providing a correspondingly improved benchmark and prior for the modeling of exoplanets with Venus-like atmospheres. We further demonstrate that these improvement factors are larger for the cloud-free atmospheric case, where the opacity floor is set by gas-phase processes rather than aerosols, because the pre-DAVINCI data are most discrepant in the sub-cloud region. Our results highlight the importance of Venus for the atmospheric characterization of rocky exoplanets in the JWST and HWO era, and demonstrate how DAVINCI measurements will directly improve exoplanet atmospheric modeling.
Related
- Rotational broadening of exoplanet spectra in arbitrarily oriented systems: Application to reflected light
- Steepening Optical Slopes in Exoplanet Transmission Spectra with Charged Hazes
- Angular power spectrum of induced gravitational waves: breaking model and parameter degeneracies in PTA observations
- Spectral Fingerprints Beyond Degeneracies in Primordial Gravitational-Wave Sources
- Binary-black hole spin population results may be driven by prior degeneracies
BibTeX
@misc{kane2026venus,
title = {{The Venus Benchmark: Resolving Degeneracies in Terrestrial Exoplanet Spectra with DAVINCI}},
author = {Stephen R. Kane and David S. Alexander and Shahid Aslam and Giada N. Arney and James B. Garvin and Stephanie A. Getty and Amy E. Hofmann and Noam R. Izenberg and Natasha M. Johnson and Erika Kohler and Emma L. Miles},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.00147},
eprint = {2609.00147},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.00147},
}
RIS
TY - UNPB
TI - The Venus Benchmark: Resolving Degeneracies in Terrestrial Exoplanet Spectra with DAVINCI
AU - Stephen R. Kane
AU - David S. Alexander
AU - Shahid Aslam
AU - Giada N. Arney
AU - James B. Garvin
AU - Stephanie A. Getty
AU - Amy E. Hofmann
AU - Noam R. Izenberg
AU - Natasha M. Johnson
AU - Erika Kohler
AU - Emma L. Miles
PY - 2026
DA - 2026/09/10
PB - arXiv
DO - 10.48550/arxiv.2609.00147
UR - https://arxiv.org/abs/2609.00147
AB - The characterization of terrestrial exoplanets with thick, CO_2-dominated atmospheres via transmission and emission spectroscopy is limited by degeneracies between atmospheric composition, cloud structure, and surface conditions. These degeneracies are particularly acute for planets in or near the Venus Zone, where sulfuric acid aerosol layers and deep-atmosphere opacity render the lower atmosphere and surface spectroscopically inaccessible via many optical/IR wavelengths. Venus provides the only accessible analog to such worlds, yet current knowledge of its full atmospheric profile relies on decades-old in situ data with known limitations. Here we demonstrate that the forthcoming DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) mission will provide the comprehensive, high-fidelity atmospheric profile data necessary to resolve many of these degeneracies. We quantify how atmospheric profile uncertainties translate into uncertainties in modeled transmission and thermal emission spectra of CO_2-dominated terrestrial worlds, and show that the spread in the modeled Venus benchmark spectrum arising from current atmospheric profile uncertainties will decrease by factors of ∼4--5 for transmission and ∼5--15× for thermal emission after DAVINCI, providing a correspondingly improved benchmark and prior for the modeling of exoplanets with Venus-like atmospheres. We further demonstrate that these improvement factors are larger for the cloud-free atmospheric case, where the opacity floor is set by gas-phase processes rather than aerosols, because the pre-DAVINCI data are most discrepant in the sub-cloud region. Our results highlight the importance of Venus for the atmospheric characterization of rocky exoplanets in the JWST and HWO era, and demonstrate how DAVINCI measurements will directly improve exoplanet atmospheric modeling.
ER -