Reaction between H₂, CO, and H₂S over Fe, Ni metal in the solar nebula: Experimental evidence for the formation of sulfur‐bearing organic molecules and sulfides

Synthesis of refractory organic matter in the ionized gas phase of the solar nebula

“…However, theoretical studies suggest that ion–molecule reactions are unable to produce the extreme 15 N enrichments of several thousands of permils observed in some IOM hotspots, or under specific conditions only (38, 39). Other scenarios favor an origin of organics within the inner solar system via high-temperature condensation reactions, such as Fischer–Tropsch-like reactions (27, 28) or condensation reactions assisted by electric discharge, such as in the present experiment (40–42). More recently, a postaccretion scenario was proposed, via interstellar formaldehyde polymerization onto the parent body (25, 26).…”

“…23 and 24). It has been also proposed that organosynthesis could have occurred onto the parent body of chondrites via polymerization of interstellar formaldehyde (25, 26), or via Fischer−Tropsch-like reactions onto metal grains at warm temperature (e.g., 300 K or above) (27, 28). Laboratory works reproduced partially the compositional features of chondritic/cometary refractory organics, but generally failed to reproduce the large D and 15 N excesses (relative to the PSN composition) observed in the inner planets, meteorites, and comets.…”

The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter

“…In the models, FTT synthesis would have occurred primarily on metal grains (Kress and Tielens, 2001). In experiments conducted under nebula-like conditions at 473 K, the percentage of CO converted to hydrocarbons in 1000 h was relatively low (0.01-0.05%) and the products were all volatile (Llorca and Casanova, 2000). The experimental temperatures were close to the temperature ($500 K) at which reaction rates should peak under nebular conditions (Kress and Tielens, 2001).…”

Dynamic pyrometamorphism during atmospheric entry of large (˜10 micron) pyrrhotite fragments from cluster IDPs

“…First, all three non-chondritic IDPs have an Feoxide rim and disseminated Fe-oxide grains in the interior, which proves they are extraterrestrial debris that was flashheated during atmospheric entry (Fraundorf 1981;Flynn 1994;Rietmeijer 1998). Second, there is a consensus that extraterrestrial Fe-sulfides are products of condensed metallic FeNi sulfidation by H 2 S gas within circumstellar nebulae, e.g., the solar nebula (Lauretta et al 1996;Llorca and Casanova 2000;Meibom et al 1999;Zolensky and Thomas 1995). This unique origin should be considered in studies of thermally processed extraterrestrial sulfides.…”