A team of scientists from UC Santa Cruz baked meteorites at 1200 degrees Celsius and then sampled the resulting gases produced using a mass spectrometer. Overall, water was predominant, followed by large amounts of carbon monoxide and carbon dioxide, and then smaller amounts of hydrogen and hydrogen sulfide. 

These results are interesting because up until this research, most atmospheric models assumed gases with solar abundances; in other words, heavy on hydrogen and helium. As coauthor Myriam Telus explains: Based on outgassing from meteorites, however, you would expect water vapor to be the dominant gas, followed by carbon monoxide and carbon dioxide. Using solar abundances is fine for large, Jupiter-size planets that acquire their atmospheres from the solar nebula, but smaller planets are thought to get their atmospheres more from outgassing.

Putting it another way, the atmospheres of rocky planets were thought to derive mostly from the gas released due to the intense heat of pulling together all the building blocks and material as well as later volcanic eruptions and outgassing. And this research, which is published in Nature Astronomy, shows that the primitive rocky material in our own solar system contained just such gases as we see in our atmosphere. Side benefit, we can use this information to narrow down our search for certain kinds of exoplanets. Yay for science working as predicted!

More Information

UCSC press release

“Composition of terrestrial exoplanet atmospheres from meteorite outgassing experiments,” Maggie A. Thompson et al., 2021 April 15, Nature Astronomy