The origin and formation pathway of carboxylic acids on aqueously altered carbonaceous asteroids

Fundamental questions related to the origin of life are long-standing, controversial, and multifaceted, but one critical answer we are capable to provide, is that the simple organic building blocks that all life require can be created by chemical processes that took place in space. However, 'Where did the chemical processes occur?', 'How were the molecules created?', 'How abundant are they?', 'What happened after they were created?', these related questions might sound simple and yet they have not been answered to date.

The significance of answering these questions is addressed by STFC's Science Challenge "How do planetary systems support the existence of life?", and this proposal aims at tackling this challenge by studying the water-soluble organic material hosted in carbon-rich meteorites.

Meteorites, as fragments of asteroids and "leftovers" of planetary formation, present a golden opportunity to evaluate the organic building blocks hosted within them. In this proposal, we will study the water-soluble carboxylic acids in the Winchcombe, Paris and Tagish Lake meteorites that are collected immediately after their fireballs streaked across the sky. We will focus on carboxylic acids not only because they comprise cell membrane without which life cannot exist, but also are the most abundant class of soluble organic compounds in meteorites.

We will extract carboxylic acids from the meteorite samples in a newly refurbished clean laboratory at Royal Holloway University of London, and will quantify their abundance and determine their structural diversity with the use of gas chromatography mass spectroscopy (GC-MS) analysis at Imperial College London. We will then interpret where these molecules were formed in space (within or beyond our solar system - on asteroids, or in the far cold interstellar medium) by referring to their isotopic compositions. The formational relationship between carboxylic acids and amino acids will also be explored in this study as they are both biologically essential and structurally related, and their relationship sheds light on the chemical formational pathways.

This study will provide a timely impact as it build on the latest understanding of the extraterrestrial organic matter in asteroid Ryugu samples returned by JAXA's Hayabusa2 mission, and will inform imminent space exploration, sample return missions such as NASA's OSIRIS-REx mission.