Calibrated spectra of 31 fireballs

We employed direct line integration and applied ionisation corrections through Saha equations to estimate the relative atomic abundances. Our results confirmed that the H/Si value remains largely independent of meteor velocity. We show a positive correlation with photometric mass for cometary meteoroids, suggesting that larger bodies better preserve their volatile content, namely hydrogen.

This correlation persists across the meteor showers, showing a physical process related to volatile preservation rather than specific parent body composition. Our data suggest that the abundance of hydrogen in large cometary meteoroids is not only higher than in CI chondrites, but is also comparable to or higher than the measured abundances in small particles of dust from Halley's comet, depending on the assumed plasma conditions.

This work brought new constraints on the distribution and preservation of volatile elements in Solar System bodies and new insights into the potential delivery mechanisms of water to Earth. The H/Si values show no correlation with meteor velocity, but increase with photometric mass for cometary meteoroids. The prevalence of hydrogen in larger cometary meteoroids supports models where comets could be significant contributors to Earth's volatile inventory.