Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds

Abstract

We present a re-examination of mass spectral data obtained from the Pioneer Venus Large Probe Neutral Mass Spectrometer. Our interpretations of differing trace chemical species are suggestive of redox disequilibria in Venus' middle clouds. Assignments to the data (at 51.3 km) include phosphine, hydrogen sulfide, nitrous acid, nitric acid, carbon monoxide, hydrochloric acid, hydrogen cyanide, ethane, and potentially ammonia, chlorous acid, and several tentative PxOy species. All parent ions were predicated upon assignment of corresponding fragmentation products, isotopologues, and atomic species. The data reveal parent ions at varying oxidation states, implying the presence of reducing power in the clouds, and illuminating the potential for chemistries yet to be discovered. When considering the hypothetical habitability of Venus' clouds, the assignments reveal a potential signature of anaerobic phosphorus metabolism (phosphine), an electron donor for anoxygenic photosynthesis (nitrite), and major constituents of the nitrogen cycle (nitrate, nitrite, ammonia, and N2).

<5000 words, 1 figure, 1 table, several supplemental items

References in corpus (5)

• The Venusian Lower Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle for Persistence of the Venusian Aerial Biosphere
• Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds
• Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine
• A stringent upper limit of the PH${}_3$ abundance at the cloud top of Venus
• On the Robustness of Phosphine Signatures in Venus' Clouds

Cited by in corpus (23)

• Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds
• Production of Ammonia Makes Venusian Clouds Habitable and Explains Observed Cloud-Level Chemical Anomalies
• Was Venus Ever Habitable? Constraints from a Coupled Interior-Atmosphere-Redox Evolution Model
• Venus Life Finder Missions Motivation and Summary
• Re-analysis of Phosphine in Venus' Clouds
• Recovery of Spectra of Phosphine in Venus' Clouds
• Phosphine in the Venusian Atmosphere: A Strict Upper Limit from SOFIA GREAT Observations
• Low levels of sulphur dioxide contamination of Venusian phosphine spectra
• Venus' Atmospheric Chemistry and Cloud Characteristics Are Compatible with Venusian Life
• Stability of 20 Biogenic Amino Acids in Concentrated Sulfuric Acid: Implications for the Habitability of Venus' Clouds
• Astrobiological Potential of Venus Atmosphere Chemical Anomalies and Other Unexplained Cloud Properties
• Mission Architecture to Characterize Habitability of Venus Cloud Layers via an Aerial Platform
• Constraints on the production of phosphine by Venusian volcanoes
• Aerial Platform Design Options for a Life-Finding Mission at Venus
• The CO${}_2$ Profile and Analytical Model for the Pioneer Venus Large Probe Neutral Mass Spectrometer
• Venusian phosphine: a 'Wow!' signal in chemistry?
• Proposed energy-metabolisms cannot explain the atmospheric chemistry of Venus
• Expansion of landing areas on the Venus surface using resonant orbits in the Venera-D project
• Recovering Phosphine in Venus' Atmosphere from SOFIA Observations
• Simple lipids form stable higher-order structures in concentrated sulfuric acid
• On The Biomass Required To Produce Phosphine Detected In The Cloud Decks Of Venus
• Using HITRAN to Model Opacities for Planetary Atmospheres: Test case of Microwave Spectra of NH${}_3$, SO${}_2$ and PH${}_3$
• Necessary Conditions for Earthly Life Floating in the Venusian Atmosphere