Exploring the link between molecular cloud ices and chondritic organic matter in laboratory

Area of Science:

• Astrochemistry
• Planetary Science
• Organic Geochemistry

Background:

• Carbonaceous meteorites contain abundant organic matter, potentially originating from early solar system materials.
• The evolution of these organic compounds on asteroid parent bodies is crucial for understanding their origins.
• Secondary processes, like aqueous alteration, may significantly modify accreted organic matter.

Purpose of the Study:

• To investigate the transformation of organic analogs under simulated asteroid aqueous alteration conditions.
• To determine the compositional changes in organic molecules during prolonged heating and water exposure.
• To establish a link between primitive solar system ices and meteorite organic matter.

Main Methods:

• Simulated aqueous alteration of organic analogs at 150°C for up to 100 days.
• High-resolution mass spectrometry to monitor the evolution of molecular compounds.
• Analysis of changes in elemental ratios (H/C, N/C) of organic families.

Main Results:

• Significant evolution of molecular families was observed during the aqueous alteration experiments.
• A decrease in hydrogen-to-carbon (H/C) and nitrogen-to-carbon (N/C) ratios in the organic compounds.
• The resulting organic products exhibited compositional similarities to the soluble organic matter found in the Murchison meteorite.

Conclusions:

• Aqueous alteration is a key process in modifying extraterrestrial organic matter on asteroid parent bodies.
• The study provides a plausible scenario connecting the organic components of carbonaceous meteorites to the icy grains found in dense molecular clouds.
• Experimental results support the hypothesis of organic material transfer from protostellar/protoplanetary disks to early solar system bodies.