Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3310c Report Date: 09-May-96:18:23 Version: ********** Check-in Date: ********** 1.Proposal Title: IO, EUROPA AND GANYMEDE BELOW 3000 A -- CYCLE 2 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/OS Sub Category SATELLITES, RINGS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone John J. Caldwell YORK UNIVERSITY CANADA (416)665-5449 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract Observe Io and Europa with FOS G270H to search for SO_2 absorption features. Also observe Ganymede with FOS G270H for calibration. Guide-star hand-off capability is required. ------------------------------------------------------------------------------------ 8. Scientific Key Words: IO, EUROPA, GANYMEDE, SO2 ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.00 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 3310c PI: John J. Caldwell Proposal Title: IO, EUROPA AND GANYMEDE BELOW 3000 A -- CYCLE 2 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John J. Caldwell YORK UNIVERSITY CANADA ------------------------------------------------------------------------------------ 3. Description of proposed observations. This is a continuation proposal (Cycle 0 = 1285; Cycle 1 = 3309). The former observations are GHRS G200M spectra of Io to search for a gas-phase SO_2 absorption edge at 2116 A, with Ganymede as a calibrator. The current proposal using the FOS investigates a much broader spectral range, which includes many SO_2 bands with a large range of band strengths. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. ST is required to do spectroscopy below 3000 A, where SO_2 has strong features. ST will improve significantly upon the S/N ratio and spectral resolution that has been achieved by previous satellite UV studies. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The proposed observations must be made for both Io and Europa at both orbital elongations. Because each satellite has synchronous rotation with Jupiter, this insures that two independent hemispheres will be covered for each satellite. Previous studies of several kinds strongly suggest that there are significant hemispherical variations on both Io and Europa. The orbital phase of Ganymede, which is to be used as a calibrator for the HRS observations, is not critical, but eastern elongation is specified here because the Earth-facing side at that longitude is brighter. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Since all the Galilean satellites are very nearly the same size, Ganymede is an ideal calibrator for the Io and Europa observations. The complications of spherical aberration make the Ganymede spectra very important as a reference when searching for very weak absorption features on the other two satellites. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Io and Europa spectra will be reduced to albedos using HST Ganymede spectra. Absorption features will be correlated with laboratory spectra of SO_2 obtained at essentially the same resolution as the ST data. Because of the thinness of the atmosphere of Io, it is probable that sophisticated radiative transfer techniques will not be required, but that will only be determined after the initial reduction of the data. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). We have a dedicated SUN 4/280 computer and workstations, on which SDAS, IRAF and IDL have been installed, to supplement STScI computing facilities for data reduction. ------------------------------------------------------------------------------------ 13. FOS spectra of Io and Europa, with both satellites at each orbital elongation, will be obtained in the range 2210-3290A, to search for SO_2 absorption features, at resolution 2 A. For Io, these would be traces of gas from volcanic venting and for Europa, there may be some SO_2 trapped in the surface H_2O ice. Ganymede spectra will be used to remove solar and instrumental features. Page 3 ------------------------------------------------------------------------------------ 11. Address Information Name: JOHN J. CALDWELL Category: PI Institution: YORK UNIVERSITY Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3310c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: IO-EAST ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE IO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = JUPITER | STD = IO | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF IO BETWEEN 45 135, | SEP OF IO CALLISTO FROM EARTH GT 12", | SEP OF IO EUROPA FROM EARTH GT 12", | SEP OF IO GANYMEDE FROM EARTH GT 12" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=5.0, TYPE=G8V | 2 |F(2200)=2E-14 | 3 |F(2116)=1E-14 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: IO-WEST ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: ^ ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | ^ | ^ | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF IO BETWEEN 225 315, | SEP OF IO CALLISTO FROM EARTH GT 12", | SEP OF IO EUROPA FROM EARTH GT 12", | SEP OF IO GANYMEDE FROM EARTH GT 12" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=5.0, TYPE=G8V | 2 |F(2200)=2E-14 | 3 |F(2116)=1E-14 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3310c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 | TARGET NAME: EUROPA-EAST ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE EUROPA ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | ^ | STD = EUROPA | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF EUROPA BETWEEN 45 135, | SEP OF EUROPA CALLISTO FROM EARTH GT | 12", | SEP OF EUROPA IO FROM EARTH GT 12", | SEP OF EUROPA GANYMEDE FROM EARTH GT | 12" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=5.3, TYPE=G8V | 2 |F(2500)=8E-14 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 4 | TARGET NAME: EUROPA-WEST ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: ^ ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | ^ | ^ | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF EUROPA BETWEEN 225 315, | SEP OF EUROPA CALLISTO FROM EARTH GT | 12", | SEP OF EUROPA IO FROM EARTH GT 12", | SEP OF EUROPA GANYMEDE FROM EARTH GT | 12" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=5.3, TYPE=G8V | 2 |F(2500)=8E-14 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3310c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 5 | TARGET NAME: GANYMEDE-CALIB ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE GANYMEDE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | ^ | STD = GANYMEDE | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF GANYMEDE BETWEEN 45 135 | SEP OF GANYMEDE CALLISTO FROM EARTH GT | 12", | SEP OF GANYMEDE EUROPA FROM EARTH GT | 12", | SEP OF GANYMEDE IO FROM EARTH GT 12" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=4.6, TYPE=G8V | GANYMEDE'S LEADING HEMISPHERE IS 2X 2 |F(2116)=9E-14 | > THAN TRAILING HEMISPHERE IN THE 3 |F(2500)=24E-14 | UV. | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3310c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IO-EAST HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 5 S 1 1 ONBOARD ACQ FOR FAINT=160 2 1.5 BRIGHT=3200 CYCLE 2 / 1-13 ------------------------------------------------------------------------------------------------------------------------------------ 1.5 IO-EAST HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=1 1 52.8 S 1 1 ONBOARD ACQ FOR 2 LOCATE=NO 2 - 4 FAINT=0 MAP=END-POINT Comments: IMPLEMENTING THE FOLLOWING EXPOSURES WILL REQUIRE GUIDE- STAR HAND-OFF CAPABILITY. ------------------------------------------------------------------------------------------------------------------------------------ 2 IO-EAST FOS/BL ACCUM 4.3 G270H 2227- 5 4M 50 2 1 3306 ------------------------------------------------------------------------------------------------------------------------------------ 3 EUROPA-EAST FOS/BL ACCUM 4.3 G270H 2227- 5 2M 35 2 1 3306 ------------------------------------------------------------------------------------------------------------------------------------ 4 GANYMEDE- FOS/BL ACCUM 4.3 G270H 2227- 5 2M 50 3 1 CALIB 3306 ------------------------------------------------------------------------------------------------------------------------------------ 5 IO-WEST HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=5 1 5 S 1 2 ONBOARD ACQ FOR FAINT=160 2 5.5 BRIGHT=3200 ------------------------------------------------------------------------------------------------------------------------------------ 5.5 IO-WEST HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=1 1 52.8 S 1 2 ONBOARD ACQ FOR 6 LOCATE=NO 2 - 13 FAINT=0 MAP=END-POINT Comments: IMPLEMENTING THE FOLLOWING EXPOSURES WILL REQUIRE GUIDE- STAR HAND-OFF CAPABILITY. ------------------------------------------------------------------------------------------------------------------------------------ 6 IO-WEST FOS/BL ACCUM 4.3 G270H 2227- 5 4M 50 2 2 3306 ------------------------------------------------------------------------------------------------------------------------------------ 13 EUROPA-WEST FOS/BL ACCUM 4.3 G270H 2227- 5 2M 35 2 2 3306 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3310c [ 8] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE FAINT BRIGHT LOCATE=NO MAP ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category SATELLITES, RINGS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 1.5; CYCLE 2 / 1-13; ONBOARD ACQ FOR 2 - 4; ONBOARD ACQ FOR 5.5; ONBOARD ACQ FOR 6 - 13; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G270H ------------------------------------------------------------------------------------------------------------------------------------ Target Names IO-EAST IO-WEST EUROPA-EAST EUROPA-WEST GANYMEDE-CALIB ------------------------------------------------------------------------------------------------------------------------------------