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An attempt to detect transient changes in Io’s SO₂ and NaCl atmosphere

Roth, Lorenz and Boissier, Jérémie and Moullet, Arielle and Sánchez-Monge, Álvaro and de Kleer, Katherine and Yoneda, Mizuki and Hikida, Reina and Kita, Hajime and Tsuchiya, Fuminori and Blöcker, Aljona and Gladstone, G. Randall and Grodent, Denis and Ivchenko, Nickolay and Lellouch, Emmanuel and Retherford, Kurt D. and Saur, Joachim and Schilke, Peter and Strobel, Darrell and Thorwirth, Sven (2020) An attempt to detect transient changes in Io’s SO₂ and NaCl atmosphere. Icarus, 350 . Art. No. 113925. ISSN 0019-1035. doi:10.1016/j.icarus.2020.113925.

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Io’s atmosphere is predominately SO₂ that is sustained by a combination of volcanic outgassing and sublimation. The loss from the atmosphere is the main mass source for Jupiter’s large magnetosphere. Numerous previous studies attributed various transient phenomena in Io’s environment and Jupiter’s magnetosphere to a sudden change in the mass loss from the atmosphere supposedly triggered by a change in volcanic activity. Since the gas in volcanic plumes does not escape directly, such causal correlation would require a transient volcano-induced change in atmospheric abundance, which has never been observed so far. Here we report four observations of atmospheric SO₂ and NaCl from the same hemisphere of Io, obtained with the IRAM NOEMA interferometer on 11 December 2016, 14 March, 6 and 29 April 2017. These observations are compared to measurements of volcanic hot spots and Io’s neutral and plasma environment. We find a stable NaCl column density in Io’s atmosphere on the four dates. The SO₂ column density derived for December 2016 is about 30% lower compared to the SO₂ column density found in the period of March to April 2017. This increase in SO₂ from December 2016 to March 2017 might be related to increasing volcanic activity observed at several sites in spring 2017, but the stability of the volcanic trace gas NaCl and resulting decrease in NaCl/SO₂ ratio do not support this interpretation. Observed dimmings in both the sulfur ion torus and Na neutral cloud suggest rather a decrease in mass loading in the period of increasing SO₂ abundance. The dimming Na brightness and stable atmospheric NaCl furthermore dispute an earlier suggested positive correlation of the sodium cloud and the hot spot activity at Loki Patara, which considerably increased in this period. The environment of Io overall appears to be in a rather quiescent state, preventing further conclusions. Only Jupiter’s aurora morphology underwent several short-term changes, which are apparently unrelated to Io’s quiescent environment or the relatively stable atmosphere.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Roth, Lorenz0000-0003-0554-4691
Boissier, Jérémie0000-0002-1545-2136
Moullet, Arielle0000-0002-9820-1032
Sánchez-Monge, Álvaro0000-0002-3078-9482
de Kleer, Katherine0000-0002-9068-3428
Yoneda, Mizuki0000-0002-7773-7612
Hikida, Reina0000-0001-8244-2918
Kita, Hajime0000-0001-9948-5316
Tsuchiya, Fuminori0000-0003-3386-6794
Blöcker, Aljona0000-0001-9937-5950
Gladstone, G. Randall0000-0003-0060-072X
Grodent, Denis0000-0002-9938-4707
Ivchenko, Nickolay0000-0003-2422-5426
Lellouch, Emmanuel0000-0001-7168-1577
Retherford, Kurt D.0000-0001-9470-150X
Saur, Joachim0000-0003-1413-1231
Schilke, Peter0000-0003-2141-5689
Strobel, Darrell0000-0002-0944-8675
Thorwirth, Sven0000-0001-8200-6710
Additional Information:© 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license ( Received 24 March 2020, Revised 4 June 2020, Accepted 10 June 2020, Available online 12 June 2020. L. R. appreciates the support from the Swedish National Space Agency (SNSA) through grant 154/17 and the Swedish Research Council (VR) through grant 2017-04897. A. S.-M., P. S. and S. T. (Cologne) have been supported via Collaborative Research Centre 956, funded by the Deutsche Forschungsgemeinschaft, Germany (DFG; project ID 184018867) and DFG, Germany SCHL 341/15-1 (“Cologne Center for Terahertz Spectroscopy”).
Group:Astronomy Department
Funding AgencyGrant Number
Swedish National Space Agency154/17
Swedish Research Council2017-04897
Deutsche Forschungsgemeinschaft (DFG)184018867
Deutsche Forschungsgemeinschaft (DFG)SCHL 341/15-1
Subject Keywords:Io’s atmosphere; Volcanic activity; Magnetospheric variability
Record Number:CaltechAUTHORS:20200615-092222832
Persistent URL:
Official Citation:Lorenz Roth, Jeremie Boissier, Arielle Moullet, Álvaro Sánchez-Monge, Katherine de Kleer, Mizuki Yoneda, Reina Hikida, Hajime Kita, Fuminori Tsuchiya, Aljona Blöcker, G. Randall Gladstone, Denis Grodent, Nickolay Ivchenko, Emmanuel Lellouch, Kurt D. Retherford, Joachim Saur, Peter Schilke, Darrell Strobel, Sven Thorwirth, An attempt to detect transient changes in Io’s SO2 and NaCl atmosphere, Icarus, Volume 350, 2020, 113925, ISSN 0019-1035, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103911
Deposited By: Tony Diaz
Deposited On:15 Jun 2020 16:32
Last Modified:16 Nov 2021 18:26

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