Venus water loss is dominated by HCO(+) dissociative recombination. (https://pubmed.ncbi.nlm.nih.gov/38710931/)

These scientists wanted to understand why Venus, a planet similar in size to Earth, is so dry even though it likely had water in the past. They studied how water might have escaped from Venus' atmosphere over time. Previous studies suggested that Venus lost water through processes like hydrogen outflow, but the scientists found a new process called HCO(+) dissociative recombination that was not considered before.

This new process, they discovered, doubles the rate at which hydrogen escapes from Venus today. This means that more water would have been lost from the planet than previously thought. By including this new process in their calculations, the scientists were able to better explain why Venus is so dry and why its atmosphere has a high concentration of deuterium compared to Earth.

The scientists suggest that future missions to Venus should measure both HCO(+) and the escaping hydrogen to confirm their findings. This study helps us understand more about how planets can lose water over time and why Venus is so different from Earth.

Chaffin MS., Cangi EM., Gregory BS., Yelle RV., Deighan J., Elliott RD., Groller H. Venus water loss is dominated by HCO(+) dissociative recombination. Nature. 2024 May;629(8011):307-310. doi: 10.1038/s41586-024-07261-y. Epub 2024 May 6.