Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4965c Report Date: 09-May-96:20:12 Version: ********** Check-in Date: ********** 1.Proposal Title: STRUCTURE AND COMPOSITION OF TITAN'S ATMOSPHERE:CYCLE 3 HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/OS Sub Category MINOR PLANETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone John J. Caldwell YORK UNIVERSITY CANADA (416) 665-5449 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract Titan will be observed with the FOS G270H, to search for discrete absorption features and continuum Rayleigh scattering. Rayleigh scattering has not previously been detected from Titan by the OAO-2 and IUE spacecraft, despite the very thick atmosphere there, because of strong absorption by quasi-organic material. ------------------------------------------------------------------------------------ 8. Scientific Key Words: TITAN, ATMOSPHERIC CHEMISTRY ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4965c PI: John J. Caldwell Proposal Title: STRUCTURE AND COMPOSITION OF TITAN'S ATMOSPHERE:CYCLE 3 HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John J. Caldwell YORK UNIVERSITY CANADA ------------------------------------------------------------------------------------ 3. Description of proposed observations. FOS spectra with G270H will be examined for signatures of trace species such as C4H2. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. ST observations are required for their high spatial resolution, and for access to the ultraviolet between 2000 and 3000 A. Ground-based observations are completely irrelevant to this study. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Schedule near opposition if practical. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The spectra will be divided by a published Solar spectrum to give an albedo curve, which will then be examined for discrete absorption features. The continuum reflectivity will also be compared to atmospheric models. The altitude of the ultraviolet absorbing layer can be estimated because the continuum opacity, Rayleigh scattering, can be modelled very accurately. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Schedule near opposition if practical. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). We have access to dedicated SUN4/280 computer system for ST data analysis. ------------------------------------------------------------------------------------ 13. Ultraviolet spectroscopy of Titan will be analyzed for discrete absorption features and for spectral continuum trends. ------------------------------------------------------------------------------------ 11. Address Information Name: JOHN J. CALDWELL Category: PI Institution: YORK UNIVERSITY Address: PHYSICS DEPARTMENT City: NORTH YORK State: ON Zip Code: M3J 1P3 Country: CANADA Telephone: (416) 665-5449 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 4965c [ 3] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: TITAN ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE TITAN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = SATURN | STD = TITAN | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | SEP OF TITAN SATURN FROM EARTH GT 30" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=8.4 | 2 |F(2200)=4.5E-15 | 3 |F(2000)=5E-16 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: RHEA ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE RHEA ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = SATURN | STD = RHEA | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | SEP OF TITAN RHEA FROM EARTH LT 80" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=9.7 | 2 |B-V=0.78 | | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4965c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 RHEA FOS/BL ACQ/ 4.3 MIRROR FAINT=2050 1 0.66S 20 1 1 ONBOARD ACQ FOR 2 BINARY BRIGHT=103000 Comments: ALL EXPOSURES MUST BE TAKEN WITH THE SAME GUIDE-STARS. ------------------------------------------------------------------------------------------------------------------------------------ 2 TITAN FOS/BL ACQ/ 4.3 MIRROR MAP=FINE 1 0.96S 20 1 1 SEQ 1-4 NO GAP FIRMWAR CYCLE 3 / 1-4 E ONBOARD ACQ FOR 3 ------------------------------------------------------------------------------------------------------------------------------------ 3 TITAN FOS/BL ACCUM 1.0 G270H 2230- 1 24.5M 50 2 1 3309 Comments: SCHEDULE NEAR OPPOSITION IF PRACTICAL, TO MAXIMIZE FLUX. ------------------------------------------------------------------------------------------------------------------------------------ 4 TITAN FOS/BL ACQ 4.3 MIRROR 2230- 1 3.84S 20 1 1 SEQ 3-4 NON-INT 3309 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4965c [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACQ/FIRMWARE ACCUM ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FAINT=2050 BRIGHT=103000 MAP=FINE ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category MINOR PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; SEQ 1-4 NO GAP; CYCLE 3 / 1-4; ONBOARD ACQ FOR 3; SEQ 3-4 NON-INT; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G270H ------------------------------------------------------------------------------------------------------------------------------------ Target Names TITAN RHEA ------------------------------------------------------------------------------------------------------------------------------------