Two new, rare, high-effusion outburst eruptions at Rarog and Heno Paterae on Io
Abstract
Observations obtained with the near-infrared camera NIRC2, coupled to the adaptive optics system on the 10-m W.M. Keck II telescope on Mauna Kea, Hawaii, on 15 August 2013 at ∼15:30 UT revealed two large "Outburst"-class volcanic eruptions on Io. Follow-up observations five days later showed that both eruptions had substantially faded. The most energetic eruption was at Rarog Patera, at a location near 305°W, 42°S; a smaller one occurred further south at ∼310°W and ∼57°S, close to Heno Patera. Total radiant fluxes at Rarog Patera on August 15 were of order ∼500 GW/sr/μm at wavelengths between 2 and 4 μm, and close to 250 GW/sr/μm at 1.6 μm, indicative of an effective temperature of ∼1040 K over an area of ∼120 km^2, and a total thermal emission of nearly 8 TW. At Heno Patera the 4-μm flux measured ∼250 GW/sr/μm, and ∼90 GW/sr/μm at 2.2 μm, suggestive of an effective temperature of ∼720 K over an area of more than 300 km^2, and a total thermal emission of ∼5–6 TW. Fits of the Davies (Davies, A.G. [1996]. Icarus 124(1), 45–61) Io Flow Model indicate that these two eruptions are vigorous and the exposed surfaces are mostly very young, no older than 4–5 min at Rarog Patera and a few hours at Heno Patera. The model fits suggest that in both locations lava fountaining is taking place, a highly-energetic style of volcanism. Using follow-up observations taken between August 20 and September 7 we estimate peak effusion rates between 5 × 10^4 and 10^5 m^3/s.
Additional Information
© 2014 Elsevier Inc. Received 27 January 2014, Revised 8 June 2014, Accepted 10 June 2014, Available online 26 June 2014. The data presented in this paper were obtained at the W.M. Keck and Gemini Observatories. We thank the Gemini Director, Markus Kissler-Patig, and the Deputy Director and Head of Science, Nancy Levenson, for providing us with DD time (GN-2013B-DD-3) to observe Io during about a dozen nights following our initial detection of the eruption. We further thank Katherine de Kleer for valuable discussions during the data reduction phase, and Lea Hirsch for assistance with the Keck observing on August 20 and 22. We also thank Glenn Veeder and colleagues for advancing us a copy of a forthcoming paper that includes a review of past observations of Rarog and Heno Paterae. We are grateful for comments by David Williams and an anonymous referee, which helped improve the manuscript. The Keck Telescopes are operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The Gemini Observatory provides the astronomical communities in each partner country with state-of the-art astronomical facilities that allocate observing time in proportion to each country's contribution. The observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciència e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Our research was partially supported by the National Science Foundation, NSF Grant AST-1313485 to UC Berkeley. Ashley Davies thanks the NASA Outer Planets Research and Planetary Geology and Geophysics Program for support. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations of Ionian volcanoes from this Hawaiian volcano.Additional details
- Eprint ID
- 52406
- DOI
- 10.1016/j.icarus.2014.06.016
- Resolver ID
- CaltechAUTHORS:20141204-144558895
- W. M. Keck Foundation
- AST-1313485
- NSF
- NASA
- Created
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2014-12-04Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)