UVIS Auroral Movies As of June 2008 Wayne Pryor, Central Arizona College/Space Environment Technologies 8 UVIS Polar Movies in Hand! day 96 (April 6) – only 1 with disturbed solar wind conditions day 145 (some 146) (May 25-26) day (Dec 16-17) day 002 (Jan 2, period 55) day 37 (Feb 6) day 109 (April 18) day 129 (May 8) day 144 (May 23) -More in XM

Summer 2008 tasks Flat-field/animate them (7/8 done) Flat-field/animate them (7/8 done) Compare with SWIM model (1 done) Compare with SWIM model (1 done) Compare with MAPSVIEW & other data Compare with MAPSVIEW & other data Write a short highlights papers Write a short highlights papers IMOVIE projects IMOVIE projects Sketch out full paper Sketch out full paper

Sample Saturn Spectral Images EUV FUV

UVIS long-slit spectroscopy EUV channel nm FUV channel nm 64 spatial x 1024 spectral pixels Spectral imaging is done by spacecraft slews Saturn’s emissions: H Lyman-  and H 2 bands from auroras and dayglow. Reflected sunlight spectrum: Rayleigh scattering in H 2 and acetylene absorption bands

Saturn in ultraviolet (July 13, 2004): auroras! H Lyman- alpha H 2 band emission

Saturn Auroral Spectrum

EUV aurora data Feb 17, 2005 (black) Model w/o self-absorption (dashed brown) Model fit (solid brown) for H 2 = 5x10 20 cm -2 & T=500K Å Wavelength ( Å ngstroms) Relative Intensity

^ shock ^ shock

June 21 (Day 172), :30-14:30 “EUVFUV” from 35 Rs N-S-N UVIS scan Slit E-W Auroral oval imaged twice Images deconvolved Blue H 2, H emission Orange reflected sunlight Aurora changes over ~1 hour Oval 70-75S

Polar Dark Spot (2005 day 172) ratio 1st/2nd wavelengths (A) Spot in 1st image is gone at longer wavelengths (2nd image) Localized small hydrocarbons? (spectrum is noisy) Polar convergence & downwelling?

UVIS polar benzene feature? Pantos et al., 1978: broad benzene feature peaks at cross-section of ~2.7x cm 2 Model at left has C 2 H 2 mixing ratio=10 -6 off spot, 5x10 -6 on spot, with C 6 H 6 of 4x10 -9 on spot

2007 day 96 high-latitude N auroras Sub-s/c lat=51º Sub-s/c lat=51º Range=21.6 Rs Range=21.6 Rs Phase=125.4º Phase=125.4º Nine ~2 hour images Nine ~2 hour images First image shown: reflected sunlight=red First image shown: reflected sunlight=red aurora=blue aurora=blue

5º grid in lat 330º lon shown Sun at left, dawn towards top auroras 70-85N Rotation 1 Rotation North Polar Auroral Projections

U. Michigan SWIM solar wind model suggests disturbed conditions for this map M

Auroral Movie Results : 9-frame movie in H 2 band emission : 9-frame movie in H 2 band emission Shows multiple arcs at times, spiral stuff Shows multiple arcs at times, spiral stuff Auroras mostly N Auroras mostly N Generally brighter on dawn side Generally brighter on dawn side Some evidence that bright spots rotate with the planet Some evidence that bright spots rotate with the planet Patterns repeat after full rotation Patterns repeat after full rotation MAG comparisons don’t show much action: spacecraft field line passed inside the oval MAG comparisons don’t show much action: spacecraft field line passed inside the oval Intriguing comparisons with INCA energetic neutrals underway: Intriguing comparisons with INCA energetic neutrals underway: INCA equatorial spirals spiral out (going clockwise) INCA equatorial spirals spiral out (going clockwise) UVIS auroral spirals spiral in (going clockwise) UVIS auroral spirals spiral in (going clockwise) Suggests mapping of patterns onto the ionosphere (larger L- shell goes to smaller co-latitude) Suggests mapping of patterns onto the ionosphere (larger L- shell goes to smaller co-latitude)

Movie #2 Auroral Movies Days (May 25-26) 2007 Auroral Movies Days (May 25-26) 2007 UVIS_045SA_NAURMOV001_PRIME: UVIS_045SA_NAURMOV001_PRIME: UVIS_045SA_NAURMOV001_PRIME: T10:39:00 to T18:54: T10:39:00 to T18:54:00. From 17.4 Rs, spacecraft latitude 26 degrees From 17.4 Rs, spacecraft latitude 26 degrees UVIS_045SA_AURORA001_PRIME: UVIS_045SA_AURORA001_PRIME: UVIS_045SA_AURORA001_PRIME: T04:30:00 to T09:30: T04:30:00 to T09:30:00

FUV time-series of Note pattern: oval, oval+bump,oval, oval+dent,oval

Scan 3 lost in rain

auroral latitude, longitude distribution

MOVIE #2 (North) Rotation Movie 16 s integrations, ~40 minutes per frame, low-res slits (2.0; 1.5 mrads wide) 1.5 mrad->1500 km resolution (quicktime is better)

MOVIE #2 (North) Corotation Movie Black “Clock Hand” is at 330 longitude use QT MOVIE #2 (North) Corotation Movie Black “Clock Hand” is at 330 longitude use QT movie_2007_145_f_corotation.mov

Longitude distribution by frame blob near 300 stays there for several frames, then drifts in longitude as it shifts poleward in latitude

Go to Imovie version

HST comparison HST comparison UVIS sees ~corotation, best defined feature moves initially corotationally, overall at ~70% of corotation UVIS sees ~corotation, best defined feature moves initially corotationally, overall at ~70% of corotation Clarke et al report from HST that: Clarke et al report from HST that: dawn is generally bright dawn is generally bright the main oval rotates at 75% of corotation the main oval rotates at 75% of corotation bright spots move at 30-65% of corotation bright spots move at 30-65% of corotation

MOVIE #3 (North) UVIS_054SA_EUVFUV001_PRIME T23:31:00 to -351T06:31:00 Range 22.8 Rs, spacecraft at 22-23N (from odcid-1143-saturneuvfuv type: Review_54_aur,’FUV’,200 is the movie call) Or Run /idl_code/hilat3.pro Notice: spiral forms! Again notice: - double arcs dusk-midnight -spots fade as they move from dawn to noon

MOVIE #4 (North) FUV EUV UVIS_055SA_NAURMOV001_PRIME UVIS_055SA_NAURMOV001_PRIME T15:18:00 to T21:48: T15:18:00 to T21:48:00 Range 16.4 Rs, spacecraft at 37N Range 16.4 Rs, spacecraft at 37N (from odcid-1143-saturneuvfuv type: Review_55_aur,’FUV’,200 is the movie call) (from odcid-1143-saturneuvfuv type: Review_55_aur,’FUV’,200 is the movie call) Notice one frame has polar outburst in semicircle of bright beads Notice one frame has polar outburst in semicircle of bright beads

Jupiter example from Gerard

X-line explanation from Gerard

MOVIE #4 (North) FUV EUV UVIS_055SA_NAURMOV001_PRIME UVIS_055SA_NAURMOV001_PRIME T15:18:00 to T21:48: T15:18:00 to T21:48:00 Range 16.4 Rs, spacecraft at 37N Range 16.4 Rs, spacecraft at 37N (from odcid-1143-saturneuvfuv type: Review_55_aur,’FUV’,200 is the movie call) (from odcid-1143-saturneuvfuv type: Review_55_aur,’FUV’,200 is the movie call) Seems sub-corotational Seems sub-corotational

MOVIE #5 (North) UVIS_058SA_NAURMOV001_PRIME UVIS_058SA_NAURMOV001_PRIME T05:36:00 to T18:36:00 (13 hours) T05:36:00 to T18:36:00 (13 hours) Range 23.1 Rs, spacecraft at 35N Range 23.1 Rs, spacecraft at 35N Review_58_aur,’FUV’,200 is the movie call Review_58_aur,’FUV’,200 is the movie call Long movie, Long movie, Needs work, but Needs work, but Aurora again Aurora again Doubles Doubles dusk-midnight dusk-midnight 2 days before HST sees S dawn storm so this is “quiet time” 2 days before HST sees S dawn storm so this is “quiet time”

MOVIE #6 (North) UVIS_065SA_NAURMOV001_PRIME UVIS_065SA_NAURMOV001_PRIME T08:18:00 to T15:18:00 (7 hours) T08:18:00 to T15:18:00 (7 hours) Range 20.9 Rs, spacecraft at 41N Range 20.9 Rs, spacecraft at 41N Review_65_aur,’FUV’,200 is the movie call Review_65_aur,’FUV’,200 is the movie call

MOVIE #7 (North) UVIS_067SA_NAURMOV001_PRIME UVIS_067SA_NAURMOV001_PRIME T06:30:00 to T15:30:00 (9 hours) T06:30:00 to T15:30:00 (9 hours) Range 17.4 Rs, spacecraft at 51N Range 17.4 Rs, spacecraft at 51N Review_67_aur,’FUV’,200 is the movie call Review_67_aur,’FUV’,200 is the movie call

MOVIE #8 (North) UVIS_069SA_NAURMOV002_PRIME UVIS_069SA_NAURMOV002_PRIME T05:28:00 to T11:28:00 (6 hours) T05:28:00 to T11:28:00 (6 hours) Range Rs, spacecraft at N Range Rs, spacecraft at N Review_69_aur,’FUV’,200 is the movie call Review_69_aur,’FUV’,200 is the movie call

UVIS Summary Saturn Conclusions 5 New EUV/FUV movies from over the N pole shows: 5 New EUV/FUV movies from over the N pole shows: Complete auroral ovals Complete auroral ovals “Blobs” of emission rotate around the oval “Blobs” of emission rotate around the oval co-rotationally at times, sub-corotationally at others co-rotationally at times, sub-corotationally at others Dawn is favored for emission Dawn is favored for emission Double arc occurs nightside Double arc occurs nightside Variable polar emissions inside oval (sometimes!) Variable polar emissions inside oval (sometimes!)

Solar Wind Model (SWIM) Comparisons Underway

UVIS, built by the University of Colorado, watches Saturn’s ultraviolet auroras

Cassini Now Orbits Saturn

Auroral Movies and Spectroscopy from Cassini UVIS Wayne Pryor, Robert West, Ian Stewart, Larry Esposito, Alain Jouchoux, Bill McClintock, Josh Colwell, Kris Larsen, Greg Holsclaw, Don Shemansky, Joseph Ajello, Candy Hansen, John Clarke, Jacques Gustin, Denis Grodent, Jean-Claude Gerard 2007 Fall AGU Meeting in San Francisco

Other planets have auroras too!

Processes by planet Earth: solar-wind driven auroras Earth: solar-wind driven auroras Jupiter: auroras dominated by sulfur, oxygen plasma from the moon Io’s volcanoes. Main aurora is due to “co- rotation breakdown” Jupiter: auroras dominated by sulfur, oxygen plasma from the moon Io’s volcanoes. Main aurora is due to “co- rotation breakdown” Saturn: mixture of solar wind driven and internal stuff from magnetospheric plasmas rich in water products from the rings and the moon Enceladus Saturn: mixture of solar wind driven and internal stuff from magnetospheric plasmas rich in water products from the rings and the moon Enceladus

UVIS (and VIMS) are on the Cassini Orbiter

Saturn H Lyman- 

Saturn Oxygen image 130 nm (peaks ~2 Rayleighs, cloud has grams of O)

Auroral Time-Dependence: 50 day time-series moving away from Saturn near phase angle 90 with the spacecraft in the solar wind

UVIS auroral time-series as Cassini recedes from Saturn while in solar wind

Hubble Auroral Campaign Feb 17, 2005 J. Clarke, J.-C. Gerard PI’s: J. Clarke, J.-C. Gerard PI’s: Day-side S auroras by HST ACS in UV (5 orbits) Day-side S auroras by HST ACS in UV (5 orbits) Night-side N auroras by Cassini VIMS and UVIS Night-side N auroras by Cassini VIMS and UVIS Cassini VIMS_003SA_THRCYLMAP001_UVIS_FOV Cassini VIMS_003SA_THRCYLMAP001_UVIS_FOV Started T23:08:00 GMT, ran 8 h 22 m Started T23:08:00 GMT, ran 8 h 22 m Cassini at ~800,000 km range Cassini at ~800,000 km range Aurora was weak that day Aurora was weak that day

HST Campaign ACS Images: Feb 17, :20-16:5817:53-18:33 19:29-20:0921:04-21:45 22:40-23:21

HST Campaign UVIS Geometry VIMS_003SA_THRCYLMAP001

HST campaign UVIS map projection Mostly UVIS slit was too far south, but… Red=aurora Green=no aurora Auroras ~75 N

UVIS dark-side spectrum

Recent UVIS N Auroral Image: 2006 Day 303 Emission on a complete oval Generally brighter pre- midnight Emission spot visible inside the oval after midnight Sub-spacecraft lat. 45 N Range 22.6 Rs

During the recent campaign ( )

INCA-UVIS comparisons from Don Mitchell

Cassini Inca movie showing corotating blob in ring current

Cassini Revolution 42 KGS trajectory Equatorial view Meridional view During Revolution 42 Cassini moves from the dayside (day 90), through dusk to midnight between day 95 and day 98. The spacecraft moves through dawn towards noon between day 98 and 103. The spacecraft crosses the equator on day 98 –midnight (N to S), and from S to N on day 101 post-noon.

Cassini Revolution 42 KGS trajectory The spacecraft trajectory is mapped using dipole plus ring current magnetic field model Dotted lines show ionospheric co-latitude in 5º multiples from the pole. Cassini probably crosses field lines connecting to the statistical location (in the south) of the auroral oval during day near dawn, day 100 near noon, and day 97 near midnight. On day 96, the UVIS observations the s/c is at highest latitudes (mapping to ~8-11º in the ionosphere), at a local time near to dusk. (Just inside the UVIS Oval!) Northern ionosphere footprint of Cassini

UVIS observations on 96

UVIS interval

Ring Current from INCA day 145

UVIS observations fits well with SKR observations: SKR radio emission is produced by precipitating electrons when a preferred longitude region passes through a preferred local time (Warwick et al., 1981) SKR radio emission is produced by precipitating electrons when a preferred longitude region passes through a preferred local time (Warwick et al., 1981) Preferred local time is now thought to be near dawn Preferred local time is now thought to be near dawn Was used to define the Saturn longitude system Was used to define the Saturn longitude system Preferred longitude may be linked to an unconfirmed magnetic anomaly Preferred longitude may be linked to an unconfirmed magnetic anomaly Or a 2-cell plasma convection pattern (Gurnett et al., 2007) Or a 2-cell plasma convection pattern (Gurnett et al., 2007)

SKR idea (Galopeau et al., 2000)

SKR period is changing somewhat (Gurnett et al., 2005) so it may not be internal to Saturn

Plasma flow ideas (Gurnett et al., 2007; Bagenal 2007)

Sample HST STIS images (Clarke et al., 2005)

HST ACS movie from 2007 showing obvious subcorotation

What does plasma data show?

Simplified Cowley et al. Model of this radial plasma distribution (top) and where it maps to in co-latitude on the planet (bottom)

Can this all be explained? Accepted: Accepted: Preferred local time for auroras is near dawn Preferred local time for auroras is near dawn Preferred longitude exists favoring precipitation Preferred longitude exists favoring precipitation Good local time and good longitude together makes bright SKR with strong periodic signal Good local time and good longitude together makes bright SKR with strong periodic signal Problem Problem How do sub-corotating auroral blobs make the periodic SKR How do sub-corotating auroral blobs make the periodic SKR Speculation: Speculation: If sub-corotating blobs drift through the preferred longitude/local time, could that do it? If sub-corotating blobs drift through the preferred longitude/local time, could that do it? Injections into preferred longitude range would tend to be brighter; stronger current promotes co-rotation, makes most of the SKR? Injections into preferred longitude range would tend to be brighter; stronger current promotes co-rotation, makes most of the SKR? Injections of plasma into other longitudes would make dimmer auroras with sub-corotation Injections of plasma into other longitudes would make dimmer auroras with sub-corotation If sub-corotating plasma drifts to the preferred longitude, it would brighten and speed up If sub-corotating plasma drifts to the preferred longitude, it would brighten and speed up

Magnetic Anomaly “Hot Wheels” Analogy “Rod-Runner” was a device on the track at 1 location that speeds up the cars…. “Rod-Runner” was a device on the track at 1 location that speeds up the cars…. Here that location is where the preferred longitude meets the dawn side Here that location is where the preferred longitude meets the dawn side

VIMS S25 H 3 + image from Tom Momary/Kevin Baines (S25NorthPoleAuroraSumCube8053THRCLMAP002)

Saturn Day 172, 2005 Limb-fitting puts auroral oval in S range

ISS south pole methane, uv3 images

Recent Cassini Camera S Polar Image Intense storm at the site of an unusual UV spectrum

Jupiter’s UV-dark Polar Haze: persistent N-S asymmetry, like the auroral asymmetry: do the auroras make dark haze?

Saturn also has UV-dark polar haze tied to the auroras Polar Haze from Voyager PPS

Polar Haze Chemistry Several theoretical and laboratory studies suggest methane (CH 4 ) chemistry after irradiation by the auroral electrons makes UV-dark hydrocarbon haze Several theoretical and laboratory studies suggest methane (CH 4 ) chemistry after irradiation by the auroral electrons makes UV-dark hydrocarbon haze Benzene (C 6 H 6 ) is an important step in this haze formation process Benzene (C 6 H 6 ) is an important step in this haze formation process We’ve looked for benzene in the UVIS data from 2005 day 172 We’ve looked for benzene in the UVIS data from 2005 day 172

Cassini CIRS sees enhanced benzene at 14.8  m at 80S (no 90S report yet) column above 10 mb (cm -2 ) 10 mb mixing ratio 37S 1.1x x S 2.2x x10 -13

EUVFUV full spectrum NO MESA!

EUVFUV

UVIS Auroral References Esposito, L. W., et al., The Cassini Ultraviolet Imaging Spectrograph Investigation. Space Sci. Reviews, 115, , Esposito, L. W., et al., The Cassini Ultraviolet Imaging Spectrograph Investigation. Space Sci. Reviews, 115, , Esposito, L. W., et al., UVIS shows an active Saturnian system, Science, 307, , Esposito, L. W., et al., UVIS shows an active Saturnian system, Science, 307, , Ajello, J. M., et al., The Cassini Campaign Observations of the Jupiter Aurora by the Ultraviolet Imaging Spectrograph and the Space Telescope Imaging Spectrograph, Icarus 178, , Ajello, J. M., et al., The Cassini Campaign Observations of the Jupiter Aurora by the Ultraviolet Imaging Spectrograph and the Space Telescope Imaging Spectrograph, Icarus 178, , Pryor, W. R., et al., Cassini UVIS Observations of Jupiter’s Auroral Variability, Icarus 178, , Pryor, W. R., et al., Cassini UVIS Observations of Jupiter’s Auroral Variability, Icarus 178, , Nichols, J. D., et al., Response of 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: /2006JA012005, Nichols, J. D., et al., Response of 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: /2006JA012005, 2007.