NASA Quarterly UVIS Q2 - 2007 (May - July 2007)

UVIS: Accomplishments Science Highlights Obtained the first UVIS auroral movies of Saturn. Detailed modeling of spectra inner icy satellites

UVIS: Science Highlights Mapping Clumps in Saturn's Rings - May 22, 2007 This false-color image of Saturn's main rings was made by combining data from multiple star occultations using the Cassini ultraviolet imaging spectrograph (UVIS). During occultations, scientists observe the brightness of a star as the rings pass in front of the star. This provides a measurement of the amount of ring material between the spacecraft and the star. Cassini has given scientists the most detailed view yet of Saturn's densely packed B ring. Cassini found that this part of the rings is densely packed with clumps, called self-gravity wakes, separated by nearly empty gaps. These clumps in Saturn's B ring are neatly organized and constantly colliding, which surprised scientists. The clumps in Saturn's B ring, 30 to 50 meters (100 to 160 feet) across, are too small to be seen directly. However, scientists can map the distribution, shape and orientation of the clumps. Colors in this image indicate the orientation of clumps, and brightness indicates the density of ring particles. The formation of wakes is strongest in the bluer regions, where ring particles clump together in tilted wakes. Particles in the central yellow regions are too densely packed for any starlight to pass through.

UVIS: Science Highlights Hyperion's Icy Surface - July 4, 2007 In this ultraviolet image of Hyperion, produced using data taken with UVIS during the September 2005 close flyby, brightness contrasts are due to both topographic and compositional variations across the surface. The brightest regions are exposed water ice in the rim of the crater that dominates the hemisphere in view. This new ultraviolet map (left) is shown next to a previously released image (right) taken by the Imaging Science Subsystem.

UVIS: Accomplishments Publications Published this quarter 2 In Press (Went into press May-July, doesn’t include still in press from earlier quarters) 3 Submitted (Submitted May - July, doesn’t include submitted earlier but not published yet) 3 Published 2007 to date: 7 Published Entire mission 53 Presentations at scientific meetings 1: MAPS Workshop at University of Iowa, May, 2007. 1: CHARM via Telecon, May 2007. 1: Aurora Workshop, Boston University in Whitefield, New Hampshire, June 2007. 1: Magnetospheres of the Outer Planets (MOP) conference in San Antonio, Texas, June 2007. 2: AGU, Acapulco, May 2007 1: PSG, Greece, June 2007 1: IUGG, Perugia, Italy, July 2007 2: MOP, San Antonio, TX, June 2007 Public Outreach and Press Activities Press release: Cassini “Cat Scan” Maps Clumps in Saturn’s Rings - May 22, 2007 Image Press release: Hyperion’s Icy Surface - PIA09216, July 5, 2007

UVIS: Plans Plans Publications (in preparation and at least submitted) Final plans for Iapetus flyby in September 2007 Develop plan for each Enceladus flyby in the extended mission Iapetus flyby September 10 2007 Publications (in preparation and at least submitted) In preparation (includes all papers submitted up to now, but not yet published (I.e. submitted in 2006, in review, etc.) 15 2 papers in press in Icarus 1 paper in press in ApJ 2 papers submitted to JGR 2 papers submitted to Icarus 3 papers submitted to Nature 2 papers submitted to ApJ 1 paper submitted to Science 1 paper submitted to Physical Review E 1 paper submitted to Astronomy and Astrophysics Upcoming presentations at scientific meetings 2: Europlanet in Potsdam, August, 2007. (Albers, Esposito) 2: Ices, Oceans and Fire: Satellites in the Outer Solar System in Boulder, CO, August 2007. (Hansen, Esposito) 3: DPS in Orlando, Florida, October 2007. (Albers, Hansen, Hendrix) 1: PSG at JPL, October 2007 (Esposito) Public Outreach and Press Activities

Backup Material

UVIS: Publications - 2007 Tian, F., A.I.F. Stewart, O. B. Toon, K. Larsen, L. W. Esposito. 2007. Monte Carlo Simulations of the water vapor plume on Enceladus. Icarus 188, 154–161. (published January 2007) Nichols, J. D., E. J. Bunce, J. T. Clarke, S. W. H. Cowley, F. J. Crary, M. K. Dougherty, J.-C. Gerard, D. Grodent,W. R. Pryor, and A. M. Rymer. 2007. Response of Jupiter's UV auroras to interplanetary conditions as observed by theHubble Space Telescope during the Cassini fly-by campaign. J. Geophys. Res. 112, A02203, doi:10.1029/2006JA012005. (Published Feb 2007) Nichols, J. D., E. J. Bunce, J. T. Clarke, S. W. H. Cowley, J.-C. Gerard, D. Grodent, and W. R. Pryor. 2007. Response Pryorof Jupiter's UV auroras to interplanetary conditions as observed by the Hubble Space Telescope during the Cassini fly-by campaign. J. Geophys. Res. 112, A02203, doi:10.1029/2006JA012005. (Published Feb. 2007) Parkinson C.D., M-C. Liang, H. Hartman, C.J. Hansen, G. Tinetti, V. Meadows, J. L. Kirschvink, and Y.L. Yung. 2007. Enceladus: Cassini Observations and Implications for the Search for Life. A&A. 463, 353–357. DOI: 10.1051/0004-6361:20065773. (pubished Feb. 2007) Liu, X., Shemansky, D. E., and Hallett, J.T. 2007. Extreme Non-LTE H2 in comets C/2000 WM1 (LINEAR) and C/2001 A2 (LINEAR). ApJSS. 169:458—471. (published April 2007) Liang, M-C, Yung, Y. and Shemansky, D. E. 2007. Photolytically generated aerosols in the mesosphere and thermosphere of Titan. ApJL, 661: L199-L202. (Published May 2007) Cruikshank, D.P. J. B. Dalton, C. M. Dalle Ore, J. Bauer, K. Stephan, G. Filacchione, A. R. Hendrix, C. J. Hansen, A. Coradini, P. Cerroni, F. Tosi, F. Capaccioni, R. Jaumann, B. J. Buratti, R. N. Clark, R. H. Brown, R. M. Nelson, T. B. McCord, K. H. Baines, P. D. Nicholson, C. Sotin, A. W. Meyer, G. Bellucci, M. Combes, J.-P. Bibring, Y. Langevin, B. Sicardy, D. L. Matson, V. Formisano, P. Drossart and V. Mennella. 2007. The Surface Composition of Hyperion. Nature. Volume 448, 54-56. (published July 2007)

UVIS: Publications (In Press) Hendrix, A.R., C.J. Hansen. 2007. Ultraviolet Observations of Phoebe from Cassini UVIS. Icarus. (Submitted Sept. 2006, In press as of 7/07) Liang, , M-C., A. N. Heays, B. R. Lewis, S. T. Gibson, and Y. L. Yung. 2007. Source of Nitrogen Isotope Anomaly in HCN in the Atmosphere of Titan. ApJ. (Submitted June 2007, in press as of 7/07) Colwell, J.E., L. W.Esposito, M. Sremcevic, G. R. Stewart, and W. E. McClintock. 2007. Self-Gravity Wakes and Radial Structure of Saturn's B Ring. Icarus. (Submitted July 2006, in press as of 7/07)

UVIS: Publications (Submitted) Hallett, J.T., D. E. Shemansky, X. Liu. 2007. Rotational-level hydrogen chemistry model of the Cassini UVIS observed Saturn dayglow. J. Geophys. Res., (Submitted March 2006) Esposito, L.W., B. K. Meinke, J.E. Colwell, P.D. Nicholson, M.M. Hedman. 2007. Moonlets and Clumps in Saturn’s F Ring. Icarus. (submitted September 2006) Hendrix, A.R., Hansen, C.J.. The Albedo Dichotomy of Iapetus Measured at UV wavelengths. Icarus. (Submitted February 2007) Jones, G. et al. Rhea-Title Pending. Nature. (submitted February, 2007) Hansen, C.J and Hendrix, A.R. 2007. Rhea-Title pending. Nature. (Submitted February, 2007) Aguilar, A., J.M, Ajello, R.S. Mangina, G.K. James. 2007. The Electron Excited Middle UV to Near IR Spectrum of H2: Cross sections and Transition Probabilities. ApJ. (Submitted March 2007) Ajello J.M., A. Aguilar, R. S. Mangina, G. K. James, P.Geissler, L. Trafton. 2007. The Middle UV to Near IR Spectrum of Electron Excited SO2. JGR-Planets. (Submitted March, 2007). Liu, X., D.E. Shemansky, C.P. Malone, P.V. Johnson, J.M. Ajello, I. Kanik, A.N. Heays, B.R. Lewis, S.T. Gibson and G. Stark. Experimental and coupled-channels investigation of the radiative properties of the band system. ApJ. (submitted March 2007) Cruikshank, D. et al. The Surface Composition of Hyperion. Nature. (Submitted March 2007) Parkinson, C. D., A. C. Barr, M. C. Liang and Y. L. Yung. 2007. “Habitability of Enceladus: Planetary Conditions for Life”. Science. (Submitted April 2007) Brilliantov, N., N. Albers, F. Spahn, and T. Poeschel. 2007 "Collision dynamics of granular particles with adhesion" Physical Review E (Submitted April 2007) Pryor, W., P. Gangopadhyay, B. Sandel, T. Forrester, E. Quemerais, E. Moebius, L. Esposito, I. Stewart, B. McClintock, A. Jouchoux, J. Colwell, V. Izmodenov, Y. Malama, K. Tobiska, D. Shemansky, J. Ajello, C.Hansen, M. Bzowski and P. Frisch. Radiation transport of heliospheric Lyman-alpha from combined Cassini and Voyager data sets. Astronomy and Astrophysics. (to be submitted in July 2007)

UVIS: Science Presentations - 2007 2: PSG, Jan, Pasadena Colwell Esposito 1: ISSI Workshop, Feb, Bern Pryor 1: LPSC, March, League City, TX Hendrix 3: EGU, Apr., Vienna West (2) 1: MAPS Workshop at University of Iowa, May, 2007. Pryor: UVIS Observations of Saturn's Auroras 2: AGU, May, Acapulco Hansen 1: CHARM via Telecon, May 2007. 1: Aurora Workshop, Boston University in Whitefield, New Hampshire, June 2007.

UVIS: Science Presentations - 2007 Continue 1: Magnetospheres of the Outer Planets (MOP) conference in San Antonio, Texas, June 2007. Pryor: UVIS Observations of Saturn's Auroras 1: PSG, June, Greece Esposito: Cassini UVIS results on the Enceladus plume and spacecraft safety. 2: MOP, June, San Antonio, TX Ajello, J., I. Stewart, M. Stevens, K. Larsen, L. Esposito, J. Colwell, W. McClinotck, W. Pryor, G. Holsclaw: Titan UVIS Airglow Spectra: Modeling and Laboratory Studies Pryor, W., Ajello, J., Gustin, J., Esposito, L., Jouchoux, A., Colwell, J., West, R., Larsen, K., Stewart, I., McClintock, W., Shemansky, D., Hansen, C., Clarke, J., Grodent, D., Gerard, J.-C., Baines, K., Drossart, P., Simon-Miller, A., Kurth, W., Crary, F., Mitchell, D., Dougherty, M.: Cassini UVIS Observations of Saturn's Auroras 1: IUGG, July, Perugia, Italy Esposito: Voyage through the Solar System.

UVIS: Outreach - 2007 1: Press releases (JPL) Cassini “Cat Scan” Maps Clumps in Saturn’s Rings - May 22, 2007 0: Press conferences & interviews 6: EPO: Talks to school children, teachers and public Larsen: Public talk on Titan Unmasked, LASP Auditorium, Boulder. April 3. Esposito: “Saturn’s Rings May Last Forever” movie produced. Presented at EGU, April 19. Pryor: Public Talk at Central Arizona College Observatory on Cassini Saturn Results, April 20. Colwell: Two talks to 8th graders at Monarch K-8 School. “Running Rings Around Saturn” March 20. Colwell: Talk to 70 college students at Colorado School of Mines. “Running Rings Around Saturn” April 9.