Controversy on Venus: The Existence of Phosphine

In 2020, Greaves et al. concluded from two independent data sources that phosphine is present in the cloud decks of Venus. Their study focused on the fundamental first rotational transition (J = 1-0) of PH₃ and their detection of phosphine is solely based on this single transition. Given the importance of phosphine as a possible biosignature and our current understanding of the chemistry of Venus, multiple studies reanalyzed the data of Greaves et al. and determined that PH₃ was not present. The conflicting results from various astrochemical groups raise questions about the validity of the existence of PH₃ in Venus's cloud decks. From these opposing studies, the statistical reliability and interpretation of the telescope data is disputed, specifically whether or not the PH₃ line could be a) an artifact of high-order polynomials in the fitting procedure or b) a misidentification of the nearby SO₂ transition (J = 30_9,21-31_8,24). In this talk, I will discuss the original analysis of the ALMA and JCMT data, the dissenting analyses and contradictory conclusions from other studies, and the current status of the ongoing debate of PH₃ in the cloud decks of Venus.

 References 

Greaves, J. S.; Richards, A. M. S.; Bains, W.; Rimmer, P. B.; Sagawa, H.; Clements, D. L.; Seager, S.; Petkowski, J. J.; Sousa-Silva, C.; Ranjan, S.; Drabek-Maunder, E.; Fraser, H. J.; Cartwright, A.; Mueller-Wodarg, I.; Zhan, Z.; Friberg, P.; Coulson, I.; Lee, E.; Hoge, J. Phosphine Gas in the Cloud Decks of Venus. Nat. Astron. 2020, 5 (7), 655–664.  

Villanueva, G. L.; Cordiner, M.; Irwin, P. G. J.; de Pater, I.; Butler, B.; Gurwell, M.; Milam, S. N.; Nixon, C. A.; Luszcz-Cook, S. H.; Wilson, C. F.; Kofman, V.; Liuzzi, G.; Faggi, S.; Fauchez, T. J.; Lippi, M.; Cosentino, R.; Thelen, A. E.; Moullet, A.; Hartogh, P.; Molter, E. M.; Charnley, S.; Arney, G. N.; Mandell, A. M.; Biver, N.; Vandaele, A. C.; de Kleer, K. R.; Kopparapu, R. No Evidence of Phosphine in the Atmosphere of Venus from Independent Analyses. Nat. Astron. 2021, 5 (7), 631–635.  

Greaves, J. S.; Richards, A. M. S.; Bains, W.; Rimmer, P. B.; Clements, D. L.; Seager, S.; Petkowski, J. J.; Sousa-Silva, C.; Ranjan, S.; Fraser, H. J. Reply to: No Evidence of Phosphine in the Atmosphere of Venus from Independent Analyses. Nat. Astron. 2021, 5 (7), 636–639.  

Greaves, J. S.; Richards, A. M. S.; Bains, W.; Rimmer, P. B.; Sagawa, H.; Clements, D. L.; Seager, S.; Petkowski, J. J.; Sousa-Silva, C.; Ranjan, S.; Drabek-Maunder, E.; Fraser, H. J.; Cartwright, A.; Mueller-Wodarg, I.; Zhan, Z.; Friberg, P.; Coulson, I.; Lee, E.; Hoge, J. Addendum: Phosphine Gas in the Cloud Deck of Venus. Nat. Astron. 2021, 5 (7), 726–728.