Volume 643, November 2020
|Number of page(s)||4|
|Section||Letters to the Editor|
|Published online||27 October 2020|
Letter to the Editor
A stringent upper limit of the PH3 abundance at the cloud top of Venus
LESIA, Observatoire de Paris, PSL Université, CNRS, Sorbonne Université, Université de Paris, 92195 Meudon, France
2 SwRI, Div. 15, San Antonio, TX 78228, USA
3 LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, 78280 Guyancourt, France
4 Kyoto Sanyo University, Kyoto 603-855, Japan
5 School of Physics and Astronomy, Cardiff University, Cardiff, UK
6 Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
Accepted: 14 October 2020
Aims. Following the announcement of the detection of phosphine (PH3) in the cloud deck of Venus at millimeter wavelengths, we searched for other possible signatures of this molecule in the infrared range.
Methods. Since 2012, we have been observing Venus in the thermal infrared at various wavelengths to monitor the behavior of SO2 and H2O at the cloud top. We identified a spectral interval recorded in March 2015 around 950 cm−1 where a PH3 transition is present.
Results. From the absence of any feature at this frequency, we derive, on the disk-integrated spectrum, a 3-σ upper limit of 5 ppbv for the PH3 mixing ratio, which is assumed to be constant throughout the atmosphere. This limit is four times lower than the disk-integrated mixing ratio derived at millimeter wavelengths.
Conclusions. Our result places a strong constraint on the maximum PH3 abundance at the cloud top and in the lower mesosphere of Venus.
Key words: planets and satellites: atmospheres / techniques: imaging spectroscopy / infrared: planetary systems
© T. Encrenaz et al. 2020
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.