Ground-based HDO and SO2 thermal mapping on Venus between 2012 and 2022: : An update  - Observatoire de Paris Access content directly
Conference Papers Year : 2022

Ground-based HDO and SO2 thermal mapping on Venus between 2012 and 2022: : An update 

Thomas Greathouse
  • Function : Author
Rohini Giles
  • Function : Author
Thomas Widemann
Bruno Bézard


<p>Since 2012, we have been monitoring SO<sub>2</sub> and H<sub>2</sub>O (using HDO as a proxy) at the cloud top of Venus, using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF) at Maunakea Observatory. Sixteen runs have been performed between 2012 and 2022. Maps have been recorded around 1345 cm<sup>-1</sup> (7.4 microns, z = 62 km), where SO<sub>2</sub>, CO<sub>2 </sub>and HDO are observed, and around 530 cm<sup>-1 </sup>(19 microns, z = 57 km) where SO<sub>2</sub> and CO<sub>2</sub> are observed, as well as around 1162 cm<sup>-1</sup> (8.6 microns, z = 66 km) where CO<sub>2</sub> is observed. From the early beginning, SO<sub>2</sub> plumes have been identified with an evolution time scale of a few hours. In 2020, an anti-correlation has been found in the long-term evolution of H<sub>2</sub>O and SO<sub>2</sub>; in addition,&#160; the SO<sub>2</sub> plume appearance as a function of local time seems to show two maxima around the terminator, indicating the possible presence of a semi-diurnal wave (Encrenaz et al. A&A 639, A69, 2020). After two years of interruption due to the pandemia, new observations have been performed in July 2021, September 2021, November 2021, and February 2022.&#160;&#160; The main results of the new observations are listed below. (1)The SO<sub>2</sub> abundance, which had been globally increasing from 2014 until 2019, has now decreased with respect to its maximum value. (2) The anti-correlation between H<sub>2</sub>O and SO<sub>2</sub>, which was maximum between 2014 and 2019 (cc = - 0.9) does not appear clearly in the recent observations. (3) The maximum appearance of the SO<sub>2</sub> plumes at the equator and the terminators is confirmed, but appears stronger on the morning side.(4) A strong activity of the SO<sub>2 </sub>plumes is observed in September and November 2021, at a time when the disk-integrated SO<sub>2</sub> abundance is low. At the same time, thermal maps at 1162 cm<sup>-1</sup> (8.6 microns, z = 66 km) show a polar enhancement. This behavior could possibly be associated with the topography.</p> <p>&#160;</p> <p>&#160;</p> <p>&#160;</p>
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Dates and versions

obspm-03903658 , version 1 (16-12-2022)



Therese Encrenaz, Thomas Greathouse, Rohini Giles, Thomas Widemann, Bruno Bézard, et al.. Ground-based HDO and SO2 thermal mapping on Venus between 2012 and 2022: : An update . 16th Europlanet Science Congress, Sep 2022, Grenade, Spain. ⟨10.5194/epsc2022-414⟩. ⟨obspm-03903658⟩
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