Quarterly
Q4 - 2013
(August
– October 2013)
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Quarterly
Analysis of the variance in UVIS stellar occultation data of Saturn ’s rings opens up a new way to explore variations in particle sizes and the distribution of clumps across the ring system. The image above shows a distribution of average particle sizes in different regions within Saturn ’s C ring. The branch of black and red points is distinct from that of the blue and green points indicating two different populations of particles or different clumping behaviors between those regions of the ring. This analysis is part of a study in preparation for submission to Icarus . (Colwell)
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Colwell: Analysis of stellar occultation statistical properties has revealed variations in particle clumping within density waves as well as regions within the rings with different effective particle sizes. The C ring ramp is consistent with the rest of the C ring by this measure of particle size, however the morphologically similar Cassini Division ramp, in contrast, does not resemble the rest of the Cassini Division. This is not what is expected from the standard model of the formation of these structures by ballistic transport.
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Colwell: Self-gravity wake modeling making use of both VIMS and UVIS occultation data provides a new way to study the population of the smallest particles in the A ring. We find that the size of the smallest particles decreases in the outer third of the A ring, and the number of small particles increases in the outer third of the A ring.
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Esposito: A dynamical model of ring haloes around strong resonances in Saturn
’s rings can explain their general characteristics and dimensions. The analysis indicates that the resonance stirring triggers aggregate formation and fragmentation at these perturbed locations.
Quarterly
3 <date>

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Published this quarter
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In press ( Went into press Aug – Oct 2013, also includes still in press from earlier quarters )
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Submitted ( Submitted Aug – Oct 2013, also includes submitted earlier and still in review )
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Published 2013 to date (since Nov. 2012)
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Published entire mission
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7
5
12
167
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5 presentations at EPSC, London, September 8-13 (Esposito (2), Hendrix, Melin, Radioti)
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9 presentation at DPS, Denver, CO, October 6-11 2013 (Albers, Becker, Bradley, Colwell (3), Esposito,
Royer, Yung,)
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1 presentation at the IO workshop, Boulder, CO, October 12 (Hendrix)
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1: public talks
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0 : press releases
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0: press conferences (phone interviews)
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4 <date>

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Bradley: Continue investigation of ring particle albedo. Compare Saturn ring spectra with Saturn icy moon spectra. Compositional modeling of ring particles using ring particle albedo and optical constants of candidate materials
• Bradley: Compare Saturn ring spectra with Saturn icy moon spectra
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Bradley: Compositional modeling of ring particles using ring particle albedo and optical constants of candidate materials
• Colwell: Complete initial paper on stellar occultation statistics.
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Colwell: Complete new model of self-gravity wakes incorporating UVIS and VIMS occultation data.
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Colwell: Identify highest priority observations for the F Ring and Proximal orbits, including particle-tracking occultations and dedicated
UV imaging of the rings at high resolution.
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Colwell: Continue work on new self-gravity wake model.
• Colwell: Work with Becker on diffraction modeling. Begin paper preparation.
• Colwell: Paper on faint and narrow rings is in production (student Bryce Bolin is lead author).
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Colwell: Paper on self-gravity wakes is in preparation (Colwell or Jerousek lead author).
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Colwell: Submit new and updated occultation data sets to the Planetary Data System. [still pending per Josh]
• Colwell: Paper on analysis of Rev 9 solar occ diffraction signal from F ring is in preparation (student Becker is lead author).
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Yung: UVIS spectra will be analyzed using a scattering radiative transfer code, including the spherical geometry involved in the
Cassini observations. The gaseous absorptions used in the radiative model will be taken from previous papers by this group.
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In preparation (includes submitted, but not yet published) 12
• 1 paper in press in an AGU monograph on the auroras
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1 papers in press in Discoveries of Modern Science
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1 papers in review in GRL
• 1 paper in press and 2 in review in Icarus
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1 paper in press and 1 in review in JGR
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1 paper in press in J. Mol. Spectrosc.
• 1 paper in review and 1 in press in Planet. Space Sci.
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1 chapter in press in the book Titan: Surface, Atmosphere and Magnetosphere
5 <date>

Continued from last page
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• 5 presentations at AGU, San Francisco, December 9-13 (Hendrix, Colwell (3), Esposito)
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• 2: public talks
• 0: press releases
• 0: press conference (phone interview)
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6 <date>

Quarterly
7 <date>

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Ajello, J.M
, West, R.A., J. Gustin, K. Larsen, A.I.F. Stewart, L.W. Esposito, W.E. McClintock, G.M. Holsclaw, E.T.
Bradley. 2012. Cassini UVIS Observations of Titan Nightglow Spectra. JGR . VOL. 117, A12315, doi:10.1029/2012JA017888. (Published 12/22/12)
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Badman , S. V., A. Masters, H. Hasegawa, M. Fujimoto, A. Radioti, D. Grodent, N. Sergis, M. K. Dougherty, and
A. J. Coates. 2013. Bursty magnetic reconnection at Saturn's magnetopause, Geophys. Res. Lett., 40. (published
March 2013, but found out this quarter.)
• Baillié, K., Colwell, J. E., Esposito, L. W. and Lewis, M. C. 2013. Meter-sized moonlet population in Saturn ’s C ring and Cassini Division. Astron. J, 145, 171. (published May 2013)
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Bradley, E.T
., J.E. Colwell, L.W. Esposito, 2013. Scattering properties of Saturn ’s rings from Cassini UVIS spectra . Icarus, 225, 1, 726 –739. (Published July 2013)
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Brilliantov
, N.V., N. Albers, F. Spahn, T. Pöschel. 2013. Erratum: Collision dynamics of granular particles with adhesion [ Phys. Rev. E 76, 051302 (2007)]. Phys. Rev. E 87, 039904(E), doi:10.1103/PhysRevE.87.039904
(Published March 2013)
• Gérard , J.C., Gustin, J., Pryor, W.R., Grodent, D., Bonfond, B., Radioti, A., Gladstone, R.G., Clarke, J.T., Nichols,
J.D., 2013. Remote sensing of the energy of auroral electrons in Saturn ’s atmosphere: Hubble and Cassini spectral observations. Icarus , Vol. 223, Issue 1, 211
–221. (Published March 2013.)
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Hendrix , A. R., T. A. Cassidy, B.J. Buratti, C. Paranicas, C. J. Hansen, B.D. Teolis, E. Roussos, P.Kollmann, T.
Bradley, R. Johnson. 2012. Mimas
’ Far-UV Albedo: Spatial Variations.
Icarus , 220 (2012) 922
–931 (Published online July 2012, but found out April 2013.)
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Hubert, B. ., J.C. Gérard, J. Gustin, D.V. Bisikalo, V.I. Shematovich and R.G. Gladstone. 2012. Cassini-UVIS observation of dayglow FUV emissions of carbon in the thermosphere of Venus. Icarus . Volume 220, Issue 2, p.
635-646, doi: 10.1016/j.icarus.2012.06.002 (Published August 2012. Didn ’t know in time for previous report).
Continued…
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Jackman , C.M, N. Achilleos, S.W.H. Cowley, E.J. Bunce, A. Radioti, D. Grodent, S.V. Badman, M.K. Dougherty,
W. Pryor. 2013. Auroral counterpart of magnetic field dipolarizations in Saturn ’s tail, PSS . V-82 –83, 34–42.
(published July 2013)
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Radioti , A., D. Grodent, J.C. Gérard, B. Bonfond, and W. Pryor. 2013. Auroral signatures of multiple magnetopause reconnection at Saturn. GRL.
40, 1 –5. (published August 31, 2013)
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Radioti A., E. Roussos, D. Grodent, J.-
C. Gérard, N. Krupp, D. G. Mitchell, J. Gustin, B. Bonfond, and W. Pryor.
2013. Signatures of magnetospheric injections in Saturn's aurora, in press, JGR . 118, 5, 1922 –1933. (published
May 2013)
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Torres , P.J., Madhusudhanan, P., Esposito, L.W. 2013. Mathematical analysis of a model for moon-triggered clumping in Saturn's rings. Physica D. 259, 55-62. (Published September 15, 2013)
Quarterly
9 <date>

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Gurnett , D. and W. Pryor. 2012. Auroral Processes Associated with Saturn's Moon Enceladus. For inclusion in an
AGU monograph on the auroras . (Accepted spring 2012)
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Gustin , J. , J.C. Gerard, D. Grodent, G.R. Gladstone, J.T. Clarke, W.R. Pryor, V. Dols, B. Bonfond, A. Radioti, L.
Lamy, J.M. Ajello. 2012. Effects of methane on giant planet's UV emissions and implications for the auroral characteristics.
J. Mol. Spectrosc . (Accepted. March 29, 2013.)
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Esposito, L.W.E
. 2013. Saturn ’s Rings.
Discoveries in Modern Science . (Went to press August 28, 2013)
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Kammer , J.A., D.E. Shemansky, X. Zhang, Y.L. Yung. 2013. Composition of Titan's Upper Atmosphere from
Cassini UVIS EUV Stellar Occultations.
Planet. Space Sci.
(Accepted 6/12/13.)
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Lamy, L ., Prange, R. Pryor, W., Gustin, J. Badman, S., Melin, H. Stallard, T., Mitchell, D.G., Brandt, P.C. 2013.
Multi-spectral simulations diagnosis of Saturn ’s aurorae throughout a planetary rotation.
JGR-Space Physics .
(Accepted June 17, 2013)
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Nicholson , P. D., R. G. French, M. M. Hedman, E. A. Marouf, and J. E. Colwell. 2013. Noncircular Features in
Saturn ’s Rings I: The Edge of the B Ring.
Icarus.
(In press as of Sept 9, 2013)
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West , R., P. Lavvas, C. Anderson, and H. Imanaka. 2012. Titan Haze. A chapter in Titan: Surface, Atmosphere and Magnetosphere . Eds. I. Mueller-Wodarg, C. Griffith, T. Cravens and E. Lellouch. Cambridge University Press
[Cambridge Planetary Science Series]. (Accepted March 1, 2012)
Quarterly
10 <date>

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Carbary , J., D. Mitchell, and W. Pryor. 2012. Correlation of Saturn's Ultraviolet Aurora with Energetic Neutral
Atoms.
GRL . (Submitted June 28, 2012)
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Cuzzi , J. N., A. D. Whizin , R. C. Hogan, A. R. Dobrovolskis, L. Dones, M. R. Showalter, J. E. Colwell , and J. D.
Scargle 2013. Saturn ’s F Ring Core: Calm in the Midst of Chaos.
Icarus (Submitted September 2013)
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Hendrix , A.R. Shemansky, D.E. et al. 2013. Io: FUV and EUV Spectroscopy from Cassini.
Icarus . (Plan to submit in October)
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Li, C., X. Zhang, M.-C. Liang, Y.L. Yung. 2013. Eddy Diffusion Profile of Titan's Atmosphere Revealed by Cassini
Observations.
Planet. Space Sci.
(Submitted Nov. 2012.)
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Mitchell, D.G., P. C. Brandt, J.F. Carbary, W.S. Kurth, S.M. Krimigis, C. Paranicas, N. Krupp, D.C. Hamilton, B.H.
Mauk, G. B. Hospadarsky, M.K. Dougherty, W. R. Pryor. 2013. Injection, Interchange And Reconnection: Energetic
Particle Observations In Saturn's Magnetotail.
JGR . (Submitted August 15, 2013, but didn ’t know last quarter)
Quarterly
11 <date>

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• J. Colwell, J. Cooney, L.W.E. Esposito: Small Particles as Tracers of Dynamical Stirring in Saturn's Rings
Esposito, P Madhusudhanan, J Colwell, M Sremcevic: Halo Transport and Production Model
Hendrix et al.
: The ultraviolet characteristics of Enceladus.
H. Melin, T. S. Stallard, S. V. Badman, J. O'Donoghue, K. H. Baines, W. R. Pryor, and J. S. D. Blake: Simultaneous Cassini
VIMS/UVIS and ground-based observations during the 2013 auroral campaign
• A. Radioti, D. Grodent, J.C. Gérard, B. Bonfond, J. Gustin, S. Milan and W. Pryor : Auroral signatures of reconnection at
Saturn: comparison with Earth
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DPS, Denver, October 6-11, 2013
• Albers, N., Sremcevic, M., Esposito, LW: Saturn's Maxwell Ringlet from Cassini UVIS Observations
• Becker, T., Colwell, J. E., Esposito, L. W.: Measuring Particle Sizes from Diffraction Spikes at Saturn ’s Ring Edges with
Cassini UVIS Stellar Occultations.
• Bradley, E.T., Colwell, J.E., Esposito, L.W., Clark, R.: Composition and Mixing Analysis of Cassini UVIS Spectra of
Saturn ’ s Rings
Bratcher, A., Colwell, J. E.: Analysis of Bending Waves in Saturn ’s Rings .
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Colwell, J. E., Jerousek, R. G., Nicholson, P. D., Hedman, M. M., Esposito, L. W., Harbison, R., West, R. A.: Small Particle
Population in Saturn ’s A Ring from Self-Gravity Wake Observations .
Cooney, J. H., Colwell, J. E.: Higher Order Moments in the Statistics of Stellar Occultations of Saturn ’s Rings .
L.W. Esposito: Predator-Prey Model for Haloes in Saturn ’s Rings
Royer: Far-ultraviolet phase curve analysis of Mimas, Tethys and Dione and implications for the exogenic processes
• M.-C. Liang, J. Kammer, X. Zhang, D. Shemansky, Y. Yung: Revised tholin profile in the atmosphere of Titan
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• Hendrix: Cassini UVIS observations of Io's Atmosphere
Quarterly
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Esposito: APS Colloquium at CU, Boulder, CO, September 23 , Icy Breath of Enceladus.
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Hendrix: Seminar at CU-LASP, Boulder, CO, October 24. UV Spectroscopy of Solar System Moons," which will include a lot of UVIS results.
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None this quarter
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None this quarter
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13 <date>