9056( 4) - 11/21/01 15:36 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9056 Version: 4 Check-in Date: 21-Nov-2001 15:36:01 1.Proposal Title: Spectroscopic Imaging of the Atmosphere of Callisto ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Paul Feldman The Johns Hopkins University CoI: Prof. Darrell F. Strobel The Johns Hopkins University N CoI: Dr. Melissa A. McGrath Space Telescope Science Institute N CoI: Prof. H. Warren Moos The Johns Hopkins University N CoI: Dr. Brian C. Wolven The Johns Hopkins University N CoI: Mr. Kurt D. Retherford The Johns Hopkins University N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain long-slit imaging ultraviolet spectra of Callisto, using STIS with the G140L grating, to study the interaction of the Jovian plasma environment with the tenuous carbon dioxide atmosphere of this icy satellite. This spectral range is rich in emissions of CO, ionC1, ionC2, and ionO1 characteristic of CO_2 atmospheres. Recent Galileo measurements of atmospheric CO_2 infrared limb emission and the plasma density and magnetic field in the vicinity of Callisto suggest that Callisto should show emission brightness comparable to Europa and Ganymede, both of which have been successfully imaged in ultraviolet ionO1 emission by STIS. ------------------------------------------------------------------------------------ 9056( 4) - 11/21/01 15:36 - [ 2] Observations Description ------------------------ We propose to use STIS for ultraviolet imaging spectroscopy of Callisto. As in our previous observational programs on Io, Europa and Ganymede, we will center the disk of Callisto (maximum diameter ~ 1.\.''6) in the 2'' wide slit and use grating G140L and the FUV/MAMA to span the wavelength range from 1160 to 1720 Angstrom. All of the strong atomic emissions of carbon and oxygen will be well separated allowing monochromatic images in each emission to be obtained. The strongest CO Fourth Positive bands fall between the ionO1 and ionC1 multiplets although complete separation of individual bands is not possible unless the emission is highly localized on the disk of Callisto. Based on our experience with the signal-to-noise achieved on Europa and Ganymede, using 5 and 4 orbits, respectively (see Figure 1), we estimate that five orbits will be required for sufficient sensitivity on the basis of the surface brightness estimates given in the preceding section. Five orbits also spans one half of a Jovian rotation, so that a significant change of the orientation of Jupiter's magnetic field relative to Callisto occurs over the course of the observations. This will allow us to test the dependence of the observed emission morphology on the magnetic field orientation. Strong effects were seen on both Ganymede and Europa. We are requesting five contiguous orbits each for both eastern and western elongation to test the prediction that the upstream/trailing (270degreesr) hemisphere will have significantly less emission than the downstream/leading (longitude 90degreesr) hemisphere. Real Time Justification ----------------------- None None Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9056( 4) - 11/21/01 15:36 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: CALLISTO-EAST ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Callisto ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | STD=CALLISTO | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF CALLISTO BETWEEN 70 110, OLG OF | JUPITER BETWEEN 330 30 | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.65 | Eastern elongation of Callisto. The B-V = 0.86 | observations should be made near | opposition when diameter of the | satellite is largest. For cycle 10 | this is between 06-Dec-2001 and 25- | Jan-2002, which corresponds to OLG | of Jupiter between 330 and 30. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: CALLISTO-WEST ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Callisto ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | STD=CALLISTO | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF CALLISTO BETWEEN 250 290, OLG OF | JUPITER BETWEEN 330 30 | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.65 | Western elongation of Callisto. The B-V = 0.86 | observations should be made near | opposition when diameter of the | satellite is largest. For cycle 10 | this is between 06-Dec-2001 and 25- | Jan-2002, which corresponds to OLG | of Jupiter between 330 and 30. | ------------------------------------------------------------------------------------------------------------------------------------ 9056( 4) - 11/21/01 15:36 - [ 4] Visit: 01 Visit Priority: Visit Requirements: GROUP 1-2 WITHIN 10 D BETWEEN 06-Dec-2001:21:36:00.0 AND 07-Dec- 2001:09:06:00.0 BETWEEN 07-Dec-2001:21:39:00.0 AND 08-Dec-2001:09:09:00.0 BETWEEN 24-Dec-2001:12:34:00.0 AND 25-Dec-2001:00:22:00.0 On Hold Comments: Additional Comments: Visit 1 should consist of 5 contiguous orbits to ensure coverage of a single Jovian rotation. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 CALLISTO-EA STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 0.1 S ST CD P DIFFUSE-CENTER=GEOMETRIC-CENTER, CHECKBOX=31 ------------------------------------------------------------------------------------------------------------------------------------ 2 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=400 1 800 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 3 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=400 1 800 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 4 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 5 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 6 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 7 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 10 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9056( 4) - 11/21/01 15:36 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 CALLISTO-EA STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9056( 4) - 11/21/01 15:36 - [ 6] Visit: 02 Visit Priority: Visit Requirements: BETWEEN 15-Dec-2001:16:57:00.0 AND 16-Dec-2001:01:57:00.0 On Hold Comments: Additional Comments: Visit 2 should follow or precede visit 1 by the time between eastern and western elongations, approximately eight days. Each visit should consist of 5 contiguous orbits to ensure coverage of a single Jovian rotation. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 CALLISTO-WE STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 0.1 S ST CD P DIFFUSE-CENTER=GEOMETRIC-CENTER, CHECKBOX=31 ------------------------------------------------------------------------------------------------------------------------------------ 22 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=400 1 800 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 23 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=400 1 800 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 24 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 25 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 26 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 27 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 28 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 29 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 30 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 31 CALLISTO-WE STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=550 1 1100 S ST UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9056( 4) - 11/21/01 15:36 - [ 7] Summary Form for Proposal 9056 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=DIFFUSE DIFFUSE-CENTER=GEOMETRIC-CENTER CHECKBOX=31 BUFFER-TIME=400 BUFFER-TIME=550 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 1-2 WITHIN 10 D BETWEEN 06-Dec-2001 21 36 00.0 AND 07-Dec-2001 09 06 00.0 BETWEEN 07-Dec-2001 21 39 00.0 AND 08-Dec-2001 09 09 00.0 BETWEEN 24-Dec-2001 12 34 00.0 AND 25-Dec-2001 00 22 00.0 BETWEEN 15-Dec-2001 16 57 00.0 AND 16-Dec-2001 01 57 00.0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names CALLISTO-EAST CALLISTO-WEST ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 ------------------------------------------------------------------------------------------------------------------------------------