Comparison of simulated and measured nicotinic acid abundance in carbonaceous chondrites and asteroid (162173) Ryugu. The density of the rock is 3 g cm−3, the porosity is 0.2, [56–58] And an ice density of 0.917 g cm-3 that completely fills the pore (after all radionuclides have decayed and water activity has ceased) is characteristic of planetesimals/carbonaceous chondrites that serve as hosts for chemosynthesis. was assumed as. The simulation was performed at a pressure of 100 bar. From left to right, the plotted bars represent the simulated molecular abundance of nicotinic acid over the entire temperature range of liquid water (leftmost solid black line) and that of his Cb asteroid (162173) collected by Ryugu. It shows the abundance measured in the sample. During the Hayabusa2 spacecraft mission, [14] In CI Chondrite Orgeir, [14] some Antarctic CM2 chondrites, [12] CM2 chondrites Murchison and Murray and ungrouped C2 chondrites Tagish Lake [13] As lines and shaded ranges listed in the legend. Because thermochemical equilibrium simulations cannot distinguish between isomers, the measured nicotinic acid abundance and the sum of all isomers (nicotinic acid, isonicotinic acid, and picolinic acid) are displayed each time. The type of extraction method used (hot water, cold water sonication, HCl hydrolysis, formic acid) is shown next to each panel. A tabular format of the data presented here is available in the Supporting Information, Table S1. — astro-ph.EP
Water chemistry within carbonaceous planetesimals holds promise for the synthesis of prebiotic organic materials essential for all life.
Meteorites derived from these planetesimals could bring these building blocks of life to early Earth, facilitating the origin of life.
Here we studied the formation of vitamin B3, a key precursor for the coenzyme NAD(P)(H), which is essential for the metabolism of all life as we know it. We propose a new reaction mechanism based on known experiments in the literature describing the synthesis of vitamin B3.
It combines the sugar precursor glyceraldehyde or dihydroxyacetone with the amino acid aspartic acid or asparagine in aqueous solution without the use of oxygen or other oxidizing agents. Thermochemical equilibrium calculations were performed to test the thermodynamic favorability. The vitamin B3 abundance predicted by this new pathway was compared with measurements in asteroids and meteorites.
We conclude that competition of reactants and hydrolytic degradation are necessary to explain the prebiotic content of meteorites. In summary, our model fits well to the complex network of chemical pathways active in this environment.
Klaus Pacek, Mijin Lee, Dmitri A. Semyonov, Thomas K. Henning
Comment: Accepted for publication on ChemPlusChem. Authors Klaus Paschek and Mijin Lee also contributed. 18 pages, 7 figures (all in color). Support information is available at this https URL.
Subject: Earth and Planetary Astrophysics (astro-ph.EP). Chemical physics (physics.chem-ph)
Quote: arXiv:2310.11433 [astro-ph.EP] (or arXiv:2310.11433v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2310.11433
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Journal reference: ChemPlusChem 2023, e202300508
Related DOI:
https://doi.org/10.1002/cplu.202300508
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Post history
From: Klaus Paschek
[v1] Tuesday, October 17, 2023 17:42:52 UTC (4,338 KB)
https://arxiv.org/abs/2310.11433
Astrobiology, astrochemistry
