6027( 8) - 04/30/96 10:25 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6027 Version: 8 Check-in Date: 30-Apr-1996 10:19:22 1.Proposal Title: HST-Galileo Io Torus Observations ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Solar System GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Nicholas M. Schneider Laboratory for Atmospheric & Space Physics, University of Colorado CoI: Melissa A. McGrath Space Telescope Science Institute N CoI: Doyle T. Hall The Johns Hopkins University N CoI: A. I. F. Stewart Laboratory for Atmospheric & Space N Physics, University of Colorado CoI: John T. Trauger Jet Propulsion Laboratory N ------------------------------------------------------------------------------------ 6. Abstract We propose observations of the Io plasma torus in coordination with the Galileo spacecraft. The requested GHRS scans are scientifically useful in and of themselves, and provide data essential to the correct interpretation of the Galileo results. The combined data set is significantly more powerful than either alone. The observations will provide the most comprehensive three-dimensional description of the plasma to date, yielding ion composition, electron density and temperature as functions of radius, magnetic longitude, and local time. Such a data set is capable of addressing major issues in Jupiter/Io science: What powers the intense torus emissions? What processes shape the Io torus? Where does mass enter the torus, and how is mass transported? In addition to Galileo and HST data, team members will oversee a thorough program of supporting EUVE and groundbased observations. ------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 2] Observations Description ------------------------ We require twelve one-orbit scans across the Io torus simultaneous with Galileo torus observations. Each ansa (side) of the torus must be scanned for six consecutive orbits (~Jupiter's rotation period) to sample the strong longitudinal variations of the torus. Both ansas must be observed to measure dawn/dusk differences. This proposal is not padded: six orbits per ansa constitutes the minimum complete data set. Anything less would seriously jeopardize the science. We intend to operate GHRS in RAPID mode, with G140L centered at 1300Angstrom\\\\ using the 1.7" large science aperture. Figure 4 shows the expected spectrum (although with longer exposure time); multiplets from SII (1256Angstrom), SIII (1194Angstrom), and SIV (1405-1423Angstrom) are easily detected. Each one-orbit scan will be targeted around the critical ribbon region of the torus near 5.9RJ (Jovian radius), and will scan +/-0.6RjJ in radial distance. Past experience (GO 5642, Figure 4) shows that acquisition and moving-target overheads limit observations to \\\\SIM 30m/orbit, and that adequate S/N is achievable in a single orbit. Standard (automatic) wavelength calibration will be adequate. RAPID mode (with the maximum 12.75s exposures) is preferable to multiple ACCUM's by virtue of much lower overheads. The total signal will be binned in radius after the observations, with resolution appropriate for the S/N of the individual lines. Co-I McGrath has extensive experience with torus observations, including interactive satellite acquisition and offsetting, scanning, etc. (e.g. McGrath et al. 1993, and GO 5642). Real Time Justification ----------------------- The observations are time-critical as they must coincide with the Galileo EUV midnight ansa scan on 19 June, 1996. Further scheduling factors (exact times, placement, drift rate and order of scans) will be completed in Phase 2. We request early confirmation of observation dates, so that we may apply for supporting groundbased, EUVE and IUE observations. Team members will coordinate a number of simultaneous programs, yielding the most complete torus data set ever obtained. Each data set has its own strengths and weaknesses - and the whole data set will greatly exceed the sum of its parts. Galileo: Coordinated by Stewart, Galileo Co-I. Observations are dictated by the spacecraft orbit, and are already fixed. EUVE: Coordinated by Hall, PI on ongoing EUVE Jupiter observations. Data are spatially-resolved extreme UV spectra of the whole torus, with lower sensitivity and spatial resolution than Galileo or HST. Observations are contingent on continued mission and approval of proposal. IUE: Coordinated by McGrath and Hall, co-I's on ongoing IUE Jupiter observations. IUE' large-slit spectra have drastically lower spatial and temporal resolution than HST. Groundbased: Coordinated by Trauger and Schneider, who have observed the torus every year since 1988. Observations are planned for Las Campanas Observatory (Chile), where we have observed for the past two years. We will image optical torus emissions for all major ion species: S+ (6716, 6731Angstrom), S+plus (9531Angstrom), O+ (3727Angstrom) and O+plus (5007Angstrom), as well as neutral sodium escaping from Io (5890Angstrom). Recent observations demonstrate that a complete filter cycle takes less than one HST orbit, yielding directly comparable longitudinal (/time) resolution. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: OVERNIGHT Email: , ------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 4] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: IO-TORUS-E ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: TORUS JUPITER ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | TYPE=TORUS,LONG=270,LAT=0,RAD=4.21E5 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | SEP OF IO-TORUS-E CALLISTO FROM EARTH GT | 10", SEP OF IO-TORUS-E EUROPA FROM EARTH | GT 10", SEP OF IO-TORUS-E GANYMEDE FROM | EARTH GT 10", SEP OF IO-TORUS-E IO FROM | EARTH GT 10" | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | SURF-LINE(1256)=8.4+/-3e-14 | MUST BE SIMULTANEOUS WITH GALILEO W-LINE(1256)=0.1 | OBSERVATIONS MINIMUM OF 10" | SEPARATION FROM ALL GALILEAN | SATELLITES | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: IO-TORUS-W ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: TORUS JUPITER ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | TYPE=TORUS,LONG=90,LAT=0,RAD=4.21E5 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | SEP OF IO-TORUS-W CALLISTO FROM EARTH GT | 10", SEP OF IO-TORUS-W EUROPA FROM EARTH | GT 10", SEP OF IO-TORUS-W GANYMEDE FROM | EARTH GT 10", SEP OF IO-TORUS-W IO FROM | EARTH GT 10" | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | SURF-LINE(1256)=8.4+/-3e-14 | MUST BE SIMULTANEOUS WITH GALILEO W-LINE(1256)=0.1 | OBSERVATIONS MINIMUM OF 10" | SEPARATION FROM ALL GALILEAN | SATELLITES | ------------------------------------------------------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 5] Visit: 01 Visit Requirements: BETWEEN 19-Jun-1996 AND 23-Jun-1996 GROUP 1-2 WITHIN 11.5H On Hold Comments: Additional Comments: Two visits must occur sequentially without interruption Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 771S SPATIAL SCAN 11 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 2 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 771S SPATIAL SCAN 21 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 3 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 4 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 5 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 6 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 7 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 8 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 9 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 10 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 11 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 12 IO-TORUS-W HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 771S SPATIAL SCAN 21 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 2 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 771S SPATIAL SCAN 11 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 3 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 4 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 5 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 6 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 7 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 8 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 9 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 10 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 11 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 2 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 12 IO-TORUS-E HRS RAPID 2.0 G140L 1300 SAMPLE- 1 938S SPATIAL SCAN 1 TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 7] Scan Paramters Form ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 1.003,1.005,1.007,1.0 FGS Scan: C Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 28.0000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0299 PA of first scan line (degrees) 82.400 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 14.0000 Width Offset (arc-sec): 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 1.004,1.006,1.008,1.0 FGS Scan: C Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 28.0000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0299 PA of first scan line (degrees) 262.400 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 14.0000 Width Offset (arc-sec): 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 11 Exposure Logsheet lines: 1.001,2.002 FGS Scan: C Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 28.0000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0363 PA of first scan line (degrees) 82.400 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 14.0000 Width Offset (arc-sec): 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 21 Exposure Logsheet lines: 1.002,2.001 FGS Scan: C Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 28.0000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0363 PA of first scan line (degrees) 262.400 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 14.0000 Width Offset (arc-sec): 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ 6027( 8) - 04/30/96 10:25 - [ 8] Summary Form for Proposal 6027 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SAMPLE-TIME=12.75 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Solar System ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 19-Jun-1996 AND 23-Jun-1996 GROUP 1-2 WITHIN 11.5H SPATIAL SCAN 11 SPATIAL SCAN 21 SPATIAL SCAN 1 SPATIAL SCAN 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names IO-TORUS-W IO-TORUS-E ------------------------------------------------------------------------------------------------------------------------------------