17825( 5) - 10-Apr-2025 16:44:48 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17825 Version: 5 Check-in Time: 10-Apr-2025 16:44:48 STScI Edit Number: 1 Title Saturn's auroral energetics at equinox: support for JWST observations ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Sarah V. Badman Lancaster University Y CoI: Dr. Henrik Melin Northumbria University N CoI: Dr. Tom Stallard Northumbria University N CoI: Dr. Luke Moore Boston University N CoI: Dr. Joe Kinrade Lancaster University N CoI: Prof. John T. Clarke Boston University N CoI: Dr. Chihiro Tao National Institute of Information and Com. N Technology (NICT) CoI: Dr. James O'Donoghue University of Reading N ------------------------------------------------------------------------------------ Abstract Saturn's aurorae are displays of light in the planet's upper atmosphere, caused by the impact of charged particles funneled along the planet's magnetic field. These powerful displays reveal where energy flows through Saturn's space environment and are a major source of atmospheric heating. In late 2024, JWST will observe Saturn's northern atmosphere in the infrared to identify a hot spot postulated to drive Saturn's curious rotating aurora. The characteristics of these rotating aurorae and their control by the atmosphere are currently unique among all planets studied. The JWST observations are therefore extremely important in providing the only way to confirm that temperature controls the generation of the rotating aurora. To fully interpret the JWST observations, we will estimate the auroral electron precipitation energy and flux using spatially-resolved UV spectra from HST/STIS across the auroral oval to determine how much energy is deposited and whether it suppports an atmospheric hot spot. We will also identify rotational phases for Saturn's northern and southern auroral ovals to constrain where and when energy is input throughout a planetary rotation. HST provides the only way to obtain the necessary spatially-resolved UV spectra and to precisely track the rotational phase of the aurora. The understanding we gain from studying our solar system planets is valuable for interpreting other systems and interactions with stellar environments, such as how remotely-detected periodic emissions can identify characteristics of exoplanet magnetospheres. ------------------------------------------------------------------------------------ Observations Description ------------------------ Images and spectra of Saturn's UV aurorae to be taken in support of JWST observations (JWST proposal GO5308). The observations will be as close in time as possible to the JWST observations (end Nov - start Dec) and separated into two sets of three consecutive orbits, with one set ideally simultaneous with JWST. Observations of the northern aurora on five orbits will follow the sequence image-spectra-image using STIS/FUV_MAMA in time-tag mode. Images will use SrF2 17825( 5) - 10-Apr-2025 16:44:48 - [ 2] filter to reduce geocoronal contamination. Spectra will use the 52x0.5" slit and G140L grating to obtain FUV spectra over 1150-1700 A at ~12 A resolution. The field of view should be centered on the northern polar region to allow the slit to cross the northern auroral region. The sixth orbit will take STIS/FUV-MAMA/SrF2 time-tag imaging of the full planet disk, including northern and southern auroral regions. Preferably the auto wavecal will be performed in occultation. ------------------------------------------------------------------------------------ 17825( 5) - 10-Apr-2025 16:44:48 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: SATURN-AURORA-NORTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Saturn-aurora-north ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN TYPE=POS_ANGLE, RAD=8, ANG=4, REF=NORTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS NOT ECL P PARTIAL OF SATURN-AURORA-NORTH BY TITAN FROM EARTH, SEP OF SATURN-AURORA-NORTH RHEA FROM EARTH GT 10", SEP OF SATURN-AURORA-NORTH TITAN FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 0.7 +/- 1 Offset with POS_ANGLE to cover northern auroral region Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 TARGET NAME: SATURN-AURORA-NS ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Saturn-aurora-image-NS ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS NOT ECL P PARTIAL OF SATURN-AURORA-NS BY TITAN FROM EARTH, SEP OF SATURN-AURORA-NS RHEA FROM EARTH GT 10", SEP OF SATURN-AURORA-NS TITAN FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 0.7 +/- 1 Image of full planet disk covering both north and south auroral regions Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ 17825( 5) - 10-Apr-2025 16:44:48 - [ 4] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 TARGET NAME: SATURN-AURORA-SOUTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Saturn-aurora-south ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN TYPE=POS_ANGLE, RAD=7.7, ANG=184, REF=NORTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS NOT ECL P PARTIAL OF SATURN-AURORA-SOUTH BY TITAN FROM EARTH, SEP OF SATURN-AURORA-SOUTH RHEA FROM EARTH GT 10", SEP OF SATURN-AURORA-SOUTH TITAN FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 0.7 +/- 1 Offset with POS_ANGLE to cover southern auroral region: ~78 deg S planetographic latitude Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ 17825( 5) - 10-Apr-2025 16:44:48 - [ 5] Visit: N1 (SaturnSaurora1) Visit Requirements: GROUP N1, N2, N3 WITHIN 12H On Hold Comments: Additional Comments: Image and spectra of southern aurora, position offset to southern polar region. 1/3 grouped orbits. Update POS_ANGLE once window confirmed. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-AURO STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=100 1 421 S (421 RA-SOUTH -MAMA G S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-AURO STIS/FUV TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=100, WAVECAL=NO 1 1300 S RA-SOUTH -MAMA G (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 52X0.05 G140L 1425 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-AURORA-SOUTH 1 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 1 N/A -MAMA G SATURN-AURORA-SOUTH 2 STIS/FUV TIME-TA 52X0.5 G140L 1425 none none none none 1 N/A -MAMA G WAVE 3 STIS/FUV ACCUM 52X0.05 G140L 1425 none none none none 1 N/A -MAMA 17825( 5) - 10-Apr-2025 16:44:48 - [ 6] Visit: N2 (SaturnNaurora2) Visit Requirements: On Hold Comments: Additional Comments: Image and spectra of northern aurora, position offset to northern polar region. 2/3 grouped orbits. Update POS_ANGLE once window confirmed. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-AURO STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=100 1 421 S (421 RA-NORTH -MAMA G S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-AURO STIS/FUV TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=100, WAVECAL=NO 1 1300 S RA-NORTH -MAMA G (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 52X0.05 G140L 1425 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-AURORA-NORTH 1 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 1 N/A -MAMA G SATURN-AURORA-NORTH 2 STIS/FUV TIME-TA 52X0.5 G140L 1425 none none none none 1 N/A -MAMA G WAVE 3 STIS/FUV ACCUM 52X0.05 G140L 1425 none none none none 1 N/A -MAMA 17825( 5) - 10-Apr-2025 16:44:48 - [ 7] Visit: N3 (SaturnSaurora3) Visit Requirements: On Hold Comments: Additional Comments: Image and spectra of southern aurora, position offset to southern polar region. 3/3 grouped orbits. Update POS_ANGLE once window confirmed. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-AURO STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=100 1 421 S (421 RA-SOUTH -MAMA G S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-AURO STIS/FUV TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=100, WAVECAL=NO 1 1300 S RA-SOUTH -MAMA G (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 52X0.05 G140L 1425 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-AURORA-SOUTH 1 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 1 N/A -MAMA G SATURN-AURORA-SOUTH 2 STIS/FUV TIME-TA 52X0.5 G140L 1425 none none none none 1 N/A -MAMA G WAVE 3 STIS/FUV ACCUM 52X0.05 G140L 1425 none none none none 1 N/A -MAMA 17825( 5) - 10-Apr-2025 16:44:48 - [ 8] Visit: N4 (SaturnNaurora4) Visit Requirements: GROUP N4, N5, N6 WITHIN 12H On Hold Comments: Additional Comments: Image and spectra of northern aurora, position offset to northern polar region. 1/3 grouped orbits. Update POS_ANGLE once window confirmed. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-AURO STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=100 1 421 S (421 RA-NORTH -MAMA G S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-AURO STIS/FUV TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=100, WAVECAL=NO 1 1300 S RA-NORTH -MAMA G (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 52X0.05 G140L 1425 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-AURORA-NORTH 1 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 1 N/A -MAMA G SATURN-AURORA-NORTH 2 STIS/FUV TIME-TA 52X0.5 G140L 1425 none none none none 1 N/A -MAMA G WAVE 3 STIS/FUV ACCUM 52X0.05 G140L 1425 none none none none 1 N/A -MAMA 17825( 5) - 10-Apr-2025 16:44:48 - [ 9] Visit: N5 (SaturnSaurora5) Visit Requirements: On Hold Comments: Additional Comments: Image and spectra of southern aurora, position offset to southern polar region. 2/3 grouped orbits. Update POS_ANGLE once window confirmed. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-AURO STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=100 1 421 S (421 RA-SOUTH -MAMA G S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-AURO STIS/FUV TIME-TA 52X0.5 G140L 1425 BUFFER-TIME=100, WAVECAL=NO 1 1300 S RA-SOUTH -MAMA G (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE STIS/FUV ACCUM 52X0.05 G140L 1425 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-AURORA-SOUTH 1 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 1 N/A -MAMA G SATURN-AURORA-SOUTH 2 STIS/FUV TIME-TA 52X0.5 G140L 1425 none none none none 1 N/A -MAMA G WAVE 3 STIS/FUV ACCUM 52X0.05 G140L 1425 none none none none 1 N/A -MAMA 17825( 5) - 10-Apr-2025 16:44:48 - [ 10] Visit: N6 (SaturnNSaurora) Visit Requirements: On Hold Comments: Additional Comments: Imaging of Saturns northern and southern aurorae. 3/3 consecutive orbits, close in time to JWST observations. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-AURO STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=100 1 2090 S RA-NS -MAMA G (2090 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-AURORA-NS 1 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 1 N/A -MAMA G 17825( 5) - 10-Apr-2025 16:44:48 - [ 11] Summary Form for Proposal 17825 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.05, 52X0.5, F25SRF2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=100, WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP N1, N2, N3 WITHIN 12H, GROUP N4, N5, N6 WITHIN 12H ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names SATURN-AURORA-NORTH, SATURN-AURORA-NS, SATURN-AURORA-SOUTH, WAVE ------------------------------------------------------------------------------------------------------------------------------------