! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /spectre/data1/aroman/proposals/6008.prop ! Generated by PREPROCESSOR, version 6.3a ! Date: Fri May 31 22:26:57 EDT 1996 Proposal_Information Title: The Atmosphere of Io and its Interaction with the Plasma Torus Proposal_Category: GO Scientific_Category: Solar System Cycle: 5 Investigators PI_Name: Gilda Ballester PI_Institution: University of Michigan CoI_Name: John Clarke CoI_Institution: University of Michigan Contact: CoI_Name: Joe Ajello CoI_Institution: Jet Propulsion Laboratory Contact: CoI_Name: Darrell Strobel CoI_Institution: Johns Hopkins University Contact: CoI_Name: Nick Schneider CoI_Institution: University of Colorado Contact: CoI_Name: Melissa McGrath CoI_Institution: Space Telescope Science Institute Contact: CoI_Name: Mike Combi CoI_Institution: University of Michigan Contact: Abstract: Post-COSTAR GHRS spectra of Io's O and S emission are of excellent quality. Spatial scans and new eclipse observations show that the emissions are dependent on the plasma torus and may change on short time scales. Far-UV WFPC2 images of Io have now shown these emissions to have an irregular morphology. Strong far-UV emissions from Jupiter associated with the foot of the Io flux tube have also been seen in WFPC2 images, and the associated processes could be related to the excitation of Io's O and S emissions. We need to characterize the temporal changes of the Io emissions to understand the interaction of the atmosphere with the torus (and Jupiter). We will make GHRS G140L observations of Io over 6 consecutive HST orbits encompassing half a torus rotation with respect to Io. These data will be obtained in mid-1996 in coordination with Galileo UVS observations of Io. We will also dedicate 2 orbits to observe Io as it goes into eclipse, and 3 more orbits as it comes out of eclipse in order to characterize the temporal changes in the emissions related to sunlight. These observations cannot be made in coordination with Galileo, and have to be made in separate visits. The GHRS exposures will use the 1.74 arcsec aperture and the G140L grating centered at 1370 and 1790 Angstroms (A) to detect various S and O multiplets. (The acquisition orbits with GHRS side 2 will be optimized with medium resolution spectra at 1479 and 1251 A to resolve various S and S+ multiplets.) Questions Observing_Description: Three visits will be made for a total of 11 HST orbits. Chronologically: 1) This visit will consist of 3 consecutive orbits dedicated to observing O and S emissions from Io's atmosphere with the GHRS as Io comes out of eclipse. These observations must be made post-opposition, best during ~ 1 Aug - 30 Sep 1995. The next opportunity would be well within Cycle 6, during the period ~ 7 Sep - 1 Nov 1996. The first orbit will include the guide star acquisition, acquisition of another Galilean satellite with GHRS side 2 and the slew to Io. During Earth occultation we will switch from side 2 to side 1. In the second orbit we will observe Io as it comes out of eclipse, taking consecutive G140L spectra centered at 1370 A with 0.5 min integration time. Similar consecutive spectra will be taken in the third orbit. 2) This visit is the main part of the program, and will consist of 6 consecutive orbits dedicated to measure the short-term variability of the O and S emissions from Io's atmosphere simultaneous with observations with the Galileo spacecraft. This 6-orbit sequence should be made on 3 July 1996 overlapping the period 06:45 - 10:52 UT when the Galileo UVS will be making spatial scans of Io. At this time Io will be visible from Earth, having passed eastern elongation and approaching inferior conjunction with Jupiter. (As of Feb 1995, the Galileo schedule seems final, but any unforeseen changes will be informed to STScI ahead of time). In case this observing time is absolutely unfeasible (eg, due to SAA problems), we could observe the closest possible in time to this period. Galileo will make another study of Io while it is eclipsed by Jupiter around 1 Jul 1996 00:00 UT, but HST will not be able to observe this eclipse from Earth since the Jovian system will be near opposition. If needed, we could observe immediately before or after this Galileo eclipse observation, before ~20:30 UT 30 Jun 1996 or after ~02:00 UT 1 Jul 1996. The first orbit will consist of the acquisition of Io with GHRS side 2 and G160M spectra centered at 1254 A (to resolve the S and S+ emissions). In the following orbits we will take consecutive (side 1) G140L spectra centered at 1370 A with 0.5 min integration time for a period of 9 to 26 min, plus an additional integration with the grating centered at 1790 A to detect additional S multiplets. Instead of requesting dark time, since the observations will be near opposition, we ask that information of the dark time window is provided to determine the contamination from Earth in the O 1304 A emission. 3) This third visit will consist of 2 consecutive orbits to observe the O and S emissions as Io goes into eclipse. These observations need to be made pre-opposition, which in Cycle 5 can only be done around 6 Mar - 5 May 1996. The first orbit will include the guide star acquisition, on-board acquisition of Io and an exposure with GHRS side 2, using the G160M centered at 1479 A. In the second orbit we will take consecutive (side 1) G140L GHRS spectra of 0.5 min integration time, centered at 1370 A, as Io goes into and during eclipse. Real_Time_Justification: The 6-orbit sequence in coordination with Galileo observations of Io is one of the primary goals of the program. Out of the possible opportunities to coordinate with Galileo, the 3 Jul 1996 from 06:45 to 10:52 UT is the only time we can make simultaneous HST and Galileo observations of Io. Any update on the Galileo scheduling will be known ahead of time (co-I J. Ajello is in the Galileo UVS team). In case it turns out to be impossible to exactly overlap the observations, two possible alternatives have been provided, but please consult us in this case. The periods requested for the Io eclipse observations will provide the adequate separation of Io from Jupiter to be observable with HST while in eclipse. Calibration_Justification: Additional_Comments: Fixed_Targets Solar_System_Targets Target_Number: 1 Target_Name: IO-EGRESS Description: SATELLITE IO Level_1: STD=JUPITER Level_2: STD=IO Level_3: Window: OLG OF JUPITER BETWEEN 240 290 Flux: SURF(V) = 5.0+/-0.5 SIZE=1.0+/-.2 F-LINE(1304)=2.1+/-1e-13 W-LINE(1304)=0.01 Comments: Target_Number: 2 Target_Name: IO-ACQ-EGRESS Description: OFFSET EUROPA Level_1: STD=JUPITER Level_2: STD=EUROPA Level_3: Window: Flux: SURF(V) = 5.3+/-0.5 SIZE=2.0+/-.2 SURF-CONT(2700)=2+/-1e-13 Comments: Acquisition for Io while in shadow for the egress observations. The strategy is to acquire Europa or Ganymede and then blind offset to Io, both in the 2 arcsec GHRS aperture. Target_Number: 3 Target_Name: IO-UVS Description: SATELLITE IO Level_1: STD=JUPITER Level_2: STD=IO Level_3: Window: OLG OF JUPITER BETWEEN 345 15 Flux: SURF(V) = 5.0+/-0.5 SIZE=1.0+/-.2 F-LINE(1304)=2.1+/-1e-13 W-LINE(1304)=0.01 Comments: Target_Number: 4 Target_Name: IO-INGRESS Description: SATELLITE IO Level_1: STD=JUPITER Level_2: STD=IO Level_3: Window: OLG OF JUPITER BETWEEN 70 120 Flux: SURF(V) = 5.0+/-0.5 SIZE=1.0+/-.2 F-LINE(1304)=2.1+/-1e-13 W-LINE(1304)=0.01 Comments: Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: BETWEEN 09-Aug-1995 AND 28-Sep-1995 On_Hold_Comments: Visit_Comments: Three consecutive orbits with GHRS to observe Io as it comes out of eclipse. Observations are possible during the post-opposition window provided for 1995. The next opportunity in 1996 is in cycle 6: BETWEEN 07-SEP-96 AND 01-NOV-96. In the 2nd orbit Io should be observed for at least ~15 min before emergence from eclipse, and at least ~15 min in sunlight. Exposure_Number: 111 Target_Name: IO-ACQ-EGRESS Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=5,LOCATE=EXTENDED Number_of_Iterations: 1 Time_Per_Exposure: 10 S Special_Requirements: ONBOARD ACQ FOR 112-132 NO SPLIT Comments: STEP-TIME = 0.2S On-board acquisition of Europa or Ganymede to offset to Io. Exposure_Number: 112 Target_Name: IO-ACQ-EGRESS Config: HRS Opmode: IMAGE Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 51.2 S Special_Requirements: END ORBIT NO SPLIT Comments: Image of Europa in LSA for pointing information. Estimated counts/dwell_point = 100. Offset to Io after this exposure. Exposure_Number: 121 Target_Name: IO-EGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 32 Time_Per_Exposure: 0.5 M Special_Requirements: NO SPLIT Comments: Exposures 121 and 122 should together cover Io about half the time when in shadow and the other half in sunlight. Exposure_Number: 122 Target_Name: IO-EGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 31 Time_Per_Exposure: 0.5 M Special_Requirements: END ORBIT NO SPLIT Comments: Exposure_Number: 131 Target_Name: IO-EGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 32 Time_Per_Exposure: 0.5 M Special_Requirements: NO SPLIT Comments: Exposure_Number: 132 Target_Name: IO-EGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 26 Time_Per_Exposure: 0.5 M Special_Requirements: END ORBIT NO SPLIT Comments: Visit_Number: 02 Visit_Requirements: BETWEEN 26-Jun-1996:02:00:00.0 AND 26-Jun-1996:03:00:00.0 ORIENT 272D TO 272D On_Hold_Comments: Visit_Comments: Six consecutive orbits with GHRS, on 26-JUL-96 overlapping the period 08:49 - 11:20 UT of the Galileo UVS Io-scan observations. In case this scheduling is really impossible, two alternative windows are provided below to make observations immediately before or after Galileo Io eclipse observations: BETWEEN 23-JUN-96:02:45 AND 23-JUN-96:19:15 and BETWEEN 24-JUN-96:00:00 AND 24-JUN-96:16:30, respectively. Exposure_Number: 211 Target_Name: IO-UVS Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=5,LOCATE=EXTENDED Number_of_Iterations: 1 Time_Per_Exposure: 10 S Special_Requirements: ONBOARD ACQ FOR 212-262 SEQ 211-213 NON-INT Comments: STEP-TIME = 0.4S On-board acquisition of Io with GHRS. Exposure_Number: 212 Target_Name: IO-UVS Config: HRS Opmode: IMAGE Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 102.4 S Special_Requirements: Comments: Image of Io in LSA for pointing information. Estimated counts/dwell_point = 100. Exposure_Number: 213 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1254. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 2 Time_Per_Exposure: 6.4 M Special_Requirements: Comments: Exposure of Io with side 2. Exposure_Number: 221 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1790. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 5 Time_Per_Exposure: 4.0 M Special_Requirements: SEQ 221-222 NON-INT Comments: Exposure_Number: 222 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 28 Time_Per_Exposure: 29.6 S Special_Requirements: Comments: Exposure_Number: 231 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1790. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 5 Time_Per_Exposure: 4.0 M Special_Requirements: SEQ 231-232 NON-INT Comments: Exposure_Number: 232 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 28 Time_Per_Exposure: 29.6 S Special_Requirements: Comments: Exposure_Number: 241 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1790. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 1 Time_Per_Exposure: 6.0 M Special_Requirements: SEQ 241-243 NON-INT Comments: Exposure_Number: 242 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 23 Time_Per_Exposure: 29.6 S Special_Requirements: Comments: Exposure_Number: 243 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 12 Time_Per_Exposure: 29.6 S Special_Requirements: Comments: Exposure_Number: 251 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 25 Time_Per_Exposure: 29.6 S Special_Requirements: SEQ 251-252 NON-INT Comments: Exposure_Number: 252 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 26 Time_Per_Exposure: 29.6 S Special_Requirements: Comments: Exposure_Number: 261 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 28 Time_Per_Exposure: 29.6 S Special_Requirements: SEQ 261-262 NON-INT Comments: Exposure_Number: 262 Target_Name: IO-UVS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1,SAA-CONTOUR=HIGH-NOISE Number_of_Iterations: 28 Time_Per_Exposure: 29.6 S Special_Requirements: Comments: Visit_Number: 03 Visit_Requirements: BETWEEN 06-Mar-1996 AND 25-Apr-1996 On_Hold_Comments: Visit_Comments: Two consecutive orbits with GHRS as Io goes into eclipse. Observations are possible during the given 1996 pre-opposition window. In the 2nd orbit Io should be observed for at least ~15 min before passing into Jupiter shadow, and at least ~15 min in shadow. Exposure_Number: 311 Target_Name: IO-INGRESS Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: SEARCH-SIZE=5,LOCATE=EXTENDED Number_of_Iterations: 1 Time_Per_Exposure: 10 S Special_Requirements: ONBOARD ACQ FOR 312-322 NO SPLIT Comments: STEP-TIME = 0.4S On-board acquisition of Io with GHRS. Exposure_Number: 312 Target_Name: IO-INGRESS Config: HRS Opmode: IMAGE Aperture: 2.0 Sp_Element: MIRROR-N2 Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 102.4 S Special_Requirements: NO SPLIT Comments: Image of Io in LSA for pointing information. Estimated counts/dwell_point = 100. Exposure_Number: 313 Target_Name: IO-INGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G160M Wavelength: 1479. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 4 Time_Per_Exposure: 209.6 S Special_Requirements: NO SPLIT Comments: Exposure of Io with side 2. Exposure_Number: 321 Target_Name: IO-INGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 32 Time_Per_Exposure: 29.6 S Special_Requirements: NO SPLIT Comments: Exposures 321 and 322 should together cover Io about half the time when in sunlight and the other half in shadow. Exposure_Number: 322 Target_Name: IO-INGRESS Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1370. Optional_Parameters: STEP-PATT=1 Number_of_Iterations: 31 Time_Per_Exposure: 29.6 S Special_Requirements: NO SPLIT Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: UPS Recipient_Email: ! Let us know what you think of this template and software! ! Please send a list of your likes and dislikes to your Program Coordinator