Venus lower atmospheric composition: analysis by gas chromatography

Area of Science:

• Planetary Science
• Atmospheric Chemistry
• Gas Chromatography

Background:

• The composition of Venus's lower atmosphere is crucial for understanding its extreme surface temperature and atmospheric dynamics.
• Previous Earth-based observations suggested gradients in atmospheric components, hinting at complex chemical processes.

Purpose of the Study:

• To conduct the first in-situ gas chromatographic analysis of Venus's lower atmosphere.
• To determine the precise concentrations of key atmospheric constituents.
• To provide data for validating atmospheric and greenhouse models of Venus.

Main Methods:

• Collection and analysis of three atmospheric samples from Venus's lower atmosphere.
• Utilized gas chromatography for precise compositional analysis.

Main Results:

• The third atmospheric sample comprised 96.4% carbon dioxide, 3.41% molecular nitrogen, 0.135% water vapor, and 186 ppm sulfur dioxide.
• Trace gases detected included molecular oxygen (69.3 ppm), argon (18.6 ppm), and neon (4.31 ppm).
• Measured abundances of water vapor and sulfur dioxide align with greenhouse model requirements for Venus's high surface temperature.

Conclusions:

• The detected levels of water vapor and sulfur dioxide support greenhouse models explaining Venus's high surface temperature.
• Observed gradients of sulfur dioxide, molecular oxygen, and water vapor support the presence of aqueous sulfuric acid clouds.
• The inventory of inert gases suggests planetary outgassing as the origin for Venus, Earth, and Mars' atmospheric components.