! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /spectre/data1/aroman/proposals/6027.prop ! Generated by PREPROCESSOR, version 6.2 ! Date: Tue Apr 30 10:17:41 EDT 1996 Proposal_Information Title: HST-Galileo Io Torus Observations Proposal_Category: GO Scientific_Category: Solar System Cycle: 5 Investigators PI_Name: Nicholas M. Schneider PI_Institution: Laboratory for Atmospheric & Space Physics, University of Colorado CoI_Name: Melissa A. McGrath CoI_Institution: Space Telescope Science Institute Contact: CoI_Name: Doyle T. Hall CoI_Institution: The Johns Hopkins University Contact: CoI_Name: A. I. F. Stewart CoI_Institution: Laboratory for Atmospheric & Space Physics, University of Colorado Contact: CoI_Name: John T. Trauger CoI_Institution: Jet Propulsion Laboratory Contact: 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. Questions Observing_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: Fixed_Targets Solar_System_Targets Target_Number: 1 Target_Name: IO-TORUS-E Description: TORUS JUPITER Level_1: STD=JUPITER Level_2: TYPE=TORUS,LONG=270,LAT=0,RAD=4.21E5 Level_3: Window: 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" Flux: SURF-LINE(1256)=8.4+/-3e-14 W-LINE(1256)=0.1 Comments: MUST BE SIMULTANEOUS WITH GALILEO OBSERVATIONS MINIMUM OF 10" SEPARATION FROM ALL GALILEAN SATELLITES Target_Number: 2 Target_Name: IO-TORUS-W Description: TORUS JUPITER Level_1: STD=JUPITER Level_2: TYPE=TORUS,LONG=90,LAT=0,RAD=4.21E5 Level_3: Window: 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" Flux: SURF-LINE(1256)=8.4+/-3e-14 W-LINE(1256)=0.1 Comments: MUST BE SIMULTANEOUS WITH GALILEO OBSERVATIONS MINIMUM OF 10" SEPARATION FROM ALL GALILEAN SATELLITES Generic_Targets Scan_Data Scan_Number: 1 FGS_Scan: Cont_or_Dwell: C Dwell_Points: Dwell_Secs: Scan_Width: 0.0 Scan_Length: 28.0 Sides_Angle: 90.0000 Number_Lines: 1 Scan_Rate: 0.029851 First_Line_PA: 82.400 Scan_Frame: CEL Length_Offset: 14.000 Width_Offset: 0.0000 Scan_Number: 2 FGS_Scan: Cont_or_Dwell: C Dwell_Points: Dwell_Secs: Scan_Width: 0.0 Scan_Length: 28.0 Sides_Angle: 90.0000 Number_Lines: 1 Scan_Rate: 0.029851 First_Line_PA: 262.400 Scan_Frame: CEL Length_Offset: 14.000 Width_Offset: 0.0000 Scan_Number: 11 FGS_Scan: Cont_or_Dwell: C Dwell_Points: Dwell_Secs: Scan_Width: 0.0 Scan_Length: 28.0 Sides_Angle: 90.0000 Number_Lines: 1 Scan_Rate: 0.036316 First_Line_PA: 82.400 Scan_Frame: CEL Length_Offset: 14.000 Width_Offset: 0.0000 Scan_Number: 21 FGS_Scan: Cont_or_Dwell: C Dwell_Points: Dwell_Secs: Scan_Width: 0.0 Scan_Length: 28.0 Sides_Angle: 90.0000 Number_Lines: 1 Scan_Rate: 0.036316 First_Line_PA: 262.400 Scan_Frame: CEL Length_Offset: 14.000 Width_Offset: 0.0000 Visits Visit_Number: 01 Visit_Requirements: BETWEEN 19-Jun-1996 AND 23-Jun-1996 GROUP 1-2 WITHIN 11.5H On_Hold_Comments: Visit_Comments: Two visits must occur sequentially without interruption Exposure_Number: 1 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 771S Special_Requirements: SPATIAL SCAN 11 Comments: Exposure_Number: 2 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 771S Special_Requirements: SPATIAL SCAN 21 Comments: Exposure_Number: 3 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 4 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 5 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 6 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 7 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 8 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 9 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 10 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 11 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 12 Target_Name: IO-TORUS-W Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 771S Special_Requirements: SPATIAL SCAN 21 Comments: Exposure_Number: 2 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 771S Special_Requirements: SPATIAL SCAN 11 Comments: Exposure_Number: 3 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 4 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 5 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 6 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 7 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 8 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 9 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 10 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Exposure_Number: 11 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 2 Comments: Exposure_Number: 12 Target_Name: IO-TORUS-E Config: HRS Opmode: RAPID Aperture: 2.0 Sp_Element: G140L Wavelength: 1300 Optional_Parameters: SAMPLE-TIME=12.75 Number_of_Iterations: 1 Time_Per_Exposure: 938S Special_Requirements: SPATIAL SCAN 1 Comments: Data_Distribution ! 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