Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 12 October 2007:
Vol. 318. no. 5848, pp. 237 - 240
DOI: 10.1126/science.1147594
Prev | Table of Contents | Next

Reports

Io's Atmospheric Response to Eclipse: UV Aurorae Observations

K. D. Retherford,1* J. R. Spencer,2 S. A. Stern,3 J. Saur,4 D. F. Strobel,5 A. J. Steffl,2 G. R. Gladstone,1 H. A. Weaver,6 A. F. Cheng,3 J. Wm. Parker,2 D. C. Slater,1 M. H. Versteeg,1 M. W. Davis,1 F. Bagenal,7 H. B. Throop,2 R. M. C. Lopes,8 D. C. Reuter,9 A. Lunsford,9 S. J. Conard,6 L. A. Young,2 J. M. Moore10

The New Horizons (NH) spacecraft observed Io's aurora in eclipse on four occasions during spring 2007. NH Alice ultraviolet spectroscopy and concurrent Hubble Space Telescope ultraviolet imaging in eclipse investigate the relative contribution of volcanoes to Io's atmosphere and its interaction with Jupiter's magnetosphere. Auroral brightness and morphology variations after eclipse ingress and egress reveal changes in the relative contribution of sublimation and volcanic sources to the atmosphere. Brightnesses viewed at different geometries are best explained by a dramatic difference between the dayside and nightside atmospheric density. Far-ultraviolet aurora morphology reveals the influence of plumes on Io's electrodynamic interaction with Jupiter's magnetosphere. Comparisons to detailed simulations of Io's aurora indicate that volcanoes supply 1 to 3% of the dayside atmosphere.

1 Southwest Research Institute, San Antonio, TX 78228, USA.
2 Southwest Research Institute, Boulder, CO 80302, USA.
3 NASA Headquarters, Washington, DC 20546, USA.
4 University of Cologne, 50923 Koln, Germany.
5 The Johns Hopkins University, Baltimore, MD 21218, USA.
6 The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
7 University of Colorado, Boulder, CO 80302, USA.
8 Jet Propulsion Laboratory, Pasadena, CA 91109, USA.
9 NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA.
10 NASA Ames Research Center, Moffett Field, CA 94035, USA.

* To whom correspondence should be addressed. E-mail: KRetherford{at}swri.edu

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Io Volcanism Seen by New Horizons: A Major Eruption of the Tvashtar Volcano.
J. R. Spencer, S. A. Stern, A. F. Cheng, H. A. Weaver, D. C. Reuter, K. Retherford, A. Lunsford, J. M. Moore, O. Abramov, R. M. C. Lopes, et al. (2007)
Science 318, 240-243
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)