Some interesting figures from the paper flagged by Tusenfem;
The peak outgassing rate, just after perihelion, was ~1200 l/s. That is roughly 20-30 x lower than that measured at Halley in 1986. It is roughly 200 x lower than that estimated for Hale-Bopp in 1997.
At the time of the final descent, the outgassing rate was estimated at ~1 l/s. This is roughly what it was when Rosetta first caught up with the comet in September 2014. Despite this low rate, the number of neutrals measured by the Rosetta COPS instrumentation was higher than at any time during the mission, due to the proximity of the craft to the comet (1/r
2, and all that).
However, even the lower of the figures above is at least 7 orders of magnitude greater than can be accounted for by Thornhill's idiotic and unscientific claims of solar wind H
+ somehow combining with pretty much non-existent O
-, to form OH, which stupid scientists then misidentify as H
2O. Such a pity that he never sees fit to explain these horrendous travesties of science that he keeps making.
Vertical structure of the near-surface expanding ionosphere of comet 67P probed by Rosetta
Heritier, K. L. et al
https://academic.oup.com/mnras/artic...e-of-comet-67P (paywalled)