# Meteoritic Abundances of Fatty Acids and Potential Reaction Pathways in Planetesimals

**Authors:** James C. -Y. Lai, Ben K. D. Pearce, Ralph E. Pudritz, Drake Lee  
**arXiv:** [1809.09779](https://arxiv.org/abs/1809.09779)  
**Date:** 2018-09-26  
**Summary page:** https://www.summarizepaper.com/en/paper/1809.09779v1/

## Key points

- Study focuses on the origin of fatty acids on prebiotic Earth and their significance in protocell membrane formation
- Researchers examine carbon-rich meteorites, specifically carbonaceous chondrites like Murchison and Tagish Lake
- Meteorites were likely delivered to early Earth through intense meteorite bombardments, making them a crucial prebiotic source of fatty acids
- Fatty acids found in these meteorites include straight-chain and branched-chain monocarboxylic and dicarboxylic acids with lengths up to 12 carbons
- Fatty acids with at least 8 carbons are necessary for vesicle formation, while modern cell membranes use lipids with approximately 12-20 carbons
- Researchers identify 11 potential abiotic fatty acid reaction pathways within meteorite parent bodies (planetesimals)
- Fischer-Tropsch-type synthesis stands out as a promising pathway for further analysis in the production of fatty acids in planetesimals
- Dominant types of fatty acids found in meteorites are straight-chain monocarboxylic acids (SCMA), followed by branched-chain monocarboxylic acids (BCMA)
- SCMA abundances vary across different types of carbonaceous chondrites, with CM2 and Tagish Lake meteorites showing concentrations ranging from 10^2 ppb to 4x10^5 ppb and from 10^4 ppb to 5x10^6 ppb respectively
- In CM, CV, and Tagish Lake meteorites, SCMA abundances generally decrease as the carbon chain length increases. However, in CR meteorites SCMA abundances peak at 5 and 6 carbons before decreasing on either side of this peak.
- Unique distribution of fatty acids in CR meteorites may suggest terrestrial contamination or different fatty acid reaction mechanisms in specific meteorite parent bodies.
- Study provides insights into abundance and distribution of fatty acids in carbonaceous chondrites and explores potential abiotic reaction pathways for their formation within planetesimals.

## Summary

This study focuses on the origin of fatty acids on the prebiotic Earth and their significance in the formation of protocell membranes. The researchers examine carbon-rich meteorites, specifically carbonaceous chondrites like Murchison and Tagish Lake, which are known to contain fatty acids. These meteorites were likely delivered to the early Earth through intense meteorite bombardments, making them a crucial prebiotic source of fatty acids. The authors collect data from various studies on the abundances of fatty acids in carbonaceous chondrites and analyze them for patterns and correlations. Fatty acids found in these meteorites include straight-chain and branched-chain monocarboxylic and dicarboxylic acids with lengths up to 12 carbons. It is worth noting that fatty acids with at least 8 carbons are necessary for vesicle formation, while modern cell membranes utilize lipids with approximately 12-20 carbons. To understand the origin of these meteoritic fatty acids, the researchers search existing literature for abiotic fatty acid reaction pathways. They identify 11 potential reactions that could produce these fatty acids within meteorite parent bodies (planetesimals). Among these reactions, Fischer-Tropsch-type synthesis stands out as a promising pathway for further analysis in the production of fatty acids in planetesimals. The dominant types of fatty acids found in meteorites are straight-chain monocarboxylic acids (SCMA), followed by branched-chain monocarboxylic acids (BCMA). SCMA abundances vary across different types of carbonaceous chondrites, with CM2 and Tagish Lake meteorites showing concentrations ranging from 10^2 parts per billion (ppb) to 4x10^5 ppb and from 10^4 ppb to 5x10^6 ppb respectively. In CM, CV, and Tagish Lake meteorites, SCMA abundances generally decrease as the carbon chain length increases. However, in CR meteorites SCMA abundances peak at 5 and 6 carbons in length before decreasing on either side of this peak. This unique distribution of fatty acids in CR meteorites may suggest terrestrial contamination or the presence of different fatty acid reaction mechanisms in specific meteorite parent bodies. Overall, this study provides valuable insights into the abundance and distribution of fatty acids in carbonaceous chondrites and explores potential abiotic reaction pathways for their formation within planetesimals. The findings contribute to our understanding of the origins of fatty acids on early Earth and their role in the development of protocell membranes.