Recovery of Phosphine in Venus' Atmosphere from SOFIA Observations by Jane S. Greaves et al. on Monday 21 November

Searches for phosphine in Venus' atmosphere have sparked a debate. Cordiner

et al. 2022 analyse spectra from the Stratospheric Observatory For Infrared

Astronomy (SOFIA) and infer <0.8 ppb of PH3. We noticed that spectral artefacts

arose mainly from inessential calibration-load signals. By-passing these

signals allows simpler post-processing, and 6.5{\sigma} detection of 1 ppb of

PH3 at ~75 km altitude (just above the clouds). Compiling six phosphine results

would suggest the abundance inverts: decreasing above the clouds but rising

again in the mesosphere from some unexplained source. However, no such extra

source is needed if phosphine is undergoing destruction by sunlight

(photolysis), as it does on Earth. Low values/limits were found where the

viewed part of the super-rotating Venusian atmosphere had passed through

sunlight, while the high values are from views moving into sunlight. We suggest

Venusian phosphine is indeed present, and so merits further work on models of

its origins.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.09852v1