9296( 14) - 10/21/03 15:22 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9296 Version: 14 Check-in Date: 21-Oct-2003 15:21:47 1.Proposal Title: Jovian Satellites ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GTO/ACS 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dr. Holland Ford The Johns Hopkins University CoI: Dr. Paul D. Feldman The Johns Hopkins University Y ------------------------------------------------------------------------------------ 5. Abstract The icy Galilean satellites form an integral but poorly understood component of Jupiter's magnetospheric system. While the Pioneer and Voyager spacecraft encounters yielded evidence for the existence of a source of oxygen ions beyond Io's orbit, conclusive evidence that Europa and Ganymede possess thin oxygen atmospheres was only recently provided by HST/GHRS detections of faint far-UV airglow emissions of OI. Moreover, the OI emission on Ganymede is localized to the region of the satellite's poles, consistent with an auroral excitation source that would be expected from the internal magnetic field of Ganymede. More recently, spectrally resolved images of Ganymede obtained with STIS have confirmed this result and demonstrated the variation in location and brightness of the OI emissions with the position of Ganymede relative to Jupiter's plasmasheet. The energy and source of the exciting electrons remain unknown and there is little or no relevant in situ Galileo data that bear directly on this question and thus the determination of the molecular abundance remains highly uncertain. However, the energy can be constrained by the observation of the forbidden OI red line at 6300 Ang, but this requires observation when the satellite is in Jupiter's shadow, to avoid the emissions being swamped by the strong solar reflected light. Europa similarly shows the UV OI emissions, and recent HST/STIS observations show a complex time-dependent variation in the spatial distribution of these emissions. Europa does not have an intrinsic magnetic field, but rather the Jovian field at Europa is modified by a magnetic field induced by Europa's rotation. We will investigate Kivelson's suggested European conducting ocean by timing observations to coincide with different orientations of the induced magnetic field. ------------------------------------------------------------------------------------ 9296( 14) - 10/21/03 15:22 - [ 2] Observations Description ------------------------ The sequence of observations is as follows: Each visit consists of one orbit of HRC observations of Ganymede in eclipse to observe OI 6300 A emissions together with two orbits of SBC observations either before or after eclipse to observe the UV oxygen emissions. Two additional orbits of STIS spectroscopy are used to verify the spectral content of the SBC images. Real Time Justification ----------------------- Observations should be made near either elongation of Jupiter so as to maximize the satellite time in eclipse and angular separation from Jupiter. The sequence of exposures is different for western elongation (pre-opposition) than for eastern elongation (post- opposition). Thus there are two observing windows, each of about three months, each year. Calibration Justification ------------------------- None Additional Comments ------------------- ------------------------------------------------------------------------------------ 9296( 14) - 10/21/03 15:22 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: GANYMEDE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Ganymede ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | STD=GANYMEDE | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF GANYMEDE FROM EARTH BETWEEN 310.0 | 360.0 | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.32+/-0.0 | Cycle 12 target. SURF(V) = 5.80 | B-V = 0.83 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: GANYMEDE-ECL ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Ganymede ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | STD=GANYMEDE | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF GANYMEDE FROM EARTH BETWEEN 310.0 | 360.0, ECL U OF GANYMEDE BY JUPITER, SEP | OF JUPITER GANYMEDE FROM EARTH GT 30.0" | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.32+/-0.0 | Cycle 12 target. Ganymede in eclipse SURF(V) = 5.80 | during one orbit. A pre-opposition B-V = 0.83 | eclipse observation should occur | within +/- 1.5 months of December 8, | 2003. Ganymede should be located in | HRC aperture so that disk of Jupiter | is excluded. | ------------------------------------------------------------------------------------------------------------------------------------ 9296( 14) - 10/21/03 15:22 - [ 4] Visit: 01 Visit Priority: Visit Requirements: SCHED 100% BETWEEN 20-OCT-2003:00:00:00 AND 20-JAN-2004:00:00:00 On Hold Comments: Additional Comments: This observation can be made either pre- or post Jupiter opposition. For the pre-opposition case each visit consists of two orbits of STIS spectroscopy followed by two orbits of ACS/SBC observations followed by one orbit of ACS/HRC observations of Ganymede in eclipse. For the post- opposition case each visit consists of one orbit of ACS/HRC observations of Ganymede in eclipse followed by two orbits of ACS/SBC observations and two orbits of STIS spectroscopy following eclipse egress. The exposure sequence given here is for PRE-OPPOSITION. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GANYMEDE STIS/C ACQ F28X50L MIRROR CHECKBOX=27,ACQTYPE=DIFFUSE, 1 0.1 S CD P DIFFUSE-CENTER=GEOMETRIC-CENTER Comments: first orbit ------------------------------------------------------------------------------------------------------------------------------------ 2 GANYMEDE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=410 1 820 S POS TARG 0,-6.8 UV-MAM G A Comments: first orbit ------------------------------------------------------------------------------------------------------------------------------------ 3 GANYMEDE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=410 1 820 S POS TARG 0,-6.8 UV-MAM G A Comments: first orbit ------------------------------------------------------------------------------------------------------------------------------------ 4 GANYMEDE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S POS TARG 0,-6.8 UV-MAM G A Comments: second orbit ------------------------------------------------------------------------------------------------------------------------------------ 5 GANYMEDE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S POS TARG 0,-6.8 UV-MAM G A Comments: second orbit ------------------------------------------------------------------------------------------------------------------------------------ 6 GANYMEDE ACS/SB ACCUM SBC F125LP 1 1250 S C Comments: third orbit ------------------------------------------------------------------------------------------------------------------------------------ 7 GANYMEDE ACS/SB ACCUM SBC F150LP 1 1250 S C Comments: third orbit ------------------------------------------------------------------------------------------------------------------------------------ 9296( 14) - 10/21/03 15:22 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 GANYMEDE ACS/SB ACCUM SBC F125LP 1 1250 S C Comments: fourth orbit ------------------------------------------------------------------------------------------------------------------------------------ 9 GANYMEDE ACS/SB ACCUM SBC F150LP 1 1250 S C Comments: fourth orbit ------------------------------------------------------------------------------------------------------------------------------------ 10 GANYMEDE-EC ACS/HR ACCUM HRC FR656N 6300 GAIN=2,CR-SPLIT=3 1 1410 S L C Comments: fifth orbit ------------------------------------------------------------------------------------------------------------------------------------ 11 GANYMEDE-EC ACS/HR ACCUM HRC FR656N 6400 GAIN=2,CR-SPLIT=2 1 940 S L C Comments: fifth orbit ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 01 1 none none none none 1 tbd 01 2 none none none none 1 tbd 01 3 none none none none 1 tbd 01 4 none none none none 2 tbd 01 5 none none none none 2 tbd 01 6 none none none none 3 1225.0 01 7 none none none none 3 1225.0 01 8 none none none none 4 tbd 01 9 none none none none 4 tbd 01 10 none none none 1 5 tbd 01 10 none none none 2 5 tbd 01 10 none none none 3 5 tbd 01 11 none none none 1 5 tbd 01 11 none none none 2 5 tbd 9296( 14) - 10/21/03 15:22 - [ 6] Summary Form for Proposal 9296 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X2 SBC HRC ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ACS/SBC ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ TIME-TAG ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CHECKBOX=27 ACQTYPE=DIFFUSE DIFFUSE-CENTER=GEOMETRIC-CENTER BUFFER-TIME=410 BUFFER-TIME=550 CR-SPLIT=3 CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GTO/ACS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 100% BETWEEN 20-OCT-2003 00 00 00 AND 20-JAN-2004 00 00 00 POS TARG 0,-6.8 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L F125LP F150LP FR656N ------------------------------------------------------------------------------------------------------------------------------------ Target Names GANYMEDE GANYMEDE-ECL ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 6300 6400 ------------------------------------------------------------------------------------------------------------------------------------