Possible Ribose Synthesis in Carbonaceous Planetesimals

Area of Science:

• Astrobiology
• Organic Chemistry
• Planetary Science

Background:

• The origin of life may involve RNA polymerization in early Earth environments.
• Ribose, a crucial component of RNA, has been detected in carbonaceous chondrites.
• Exogenous delivery of ribose to early Earth is a potential pathway to the RNA world.

Purpose of the Study:

• To investigate ribose formation via a simplified formose reaction within asteroid parent bodies.
• To model ribose abundance in planetesimals considering size and thermal history.
• To experimentally determine ribose yield in the formose reaction using asteroid-relevant catalysts.

Main Methods:

• Utilized a coupled physico-chemical model to calculate ribose abundance in planetesimals.
• Conducted laboratory experiments simulating the formose reaction with carbonaceous chondrite catalysts.
• Integrated experimental yields into the theoretical model to refine predictions of 5-carbon sugars (5Cs).

Main Results:

• Calculated ribose abundances were comparable to those measured in carbonaceous chondrites.
• The formose reaction within parent bodies is a plausible source of chondritic ribose.
• Analyzed chemical decomposition and preservation, constraining ribose's location and timing in planetesimals.

Conclusions:

• The aqueous formose reaction likely accounts for most ribose found in carbonaceous chondrites.
• Synthesis of RNA precursors within parent bodies and subsequent delivery to early Earth is supported.
• These findings contribute to understanding the extraterrestrial origins of life's building blocks.