Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1289c Report Date: 09-May-96:16:25 Version: ********** Check-in Date: ********** 1.Proposal Title: STRUCTURE AND COMPOSITION OF TITAN'S ATMOSPHERE:CYCLE 1 ------------------------------------------------------------------------------------ 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 both with ultraviolet imaging and spectroscopy. The ultraviolet imaging is to look for very high altitude atmospheric structure that might be associated with details of the UV spectroscopy. The UV spectroscopy will include a search for discrete absorption features and continuum Rayleigh scattering. Rayleigh scattering has not previously been detected from Titan, 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 1289c PI: John J. Caldwell Proposal Title: STRUCTURE AND COMPOSITION OF TITAN'S ATMOSPHERE:CYCLE 1 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John J. Caldwell YORK UNIVERSITY CANADA ------------------------------------------------------------------------------------ 3. Description of proposed observations. The observations include one FOC image, using two filters to block the red leak. The effective wavelength will be about 2400A, just shortward of the mid-range of the two FOS spectra, G270H and G190H. Complex hydrocarbons such as C2H4 will be sought. ------------------------------------------------------------------------------------ 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. There are no special requirements of these types. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The image will be examined for suggestions of contrast features at all wavelengths, and will be compared to earlier Voyager images.The spectra will be divided by a published Solar spectrum to generate an albedo curve, which will be examined for discrete absorption features. The continuum reflectivity will also be compared to atmospheric models. It should be possible to estimate the altitude of the ultraviolet absorbing layer, because the continuum opacity, Rayleigh scattering, can be modelled very accurately. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. There are no special requirements ------------------------------------------------------------------------------------ 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 and imaging of Tital will be obtained. The imaging complements the Voyager data set, at a different wavelength, where the atmosphere is known to absorb very strongly. The spectra will be analyzed for discrete absorptionfeatures. ------------------------------------------------------------------------------------ 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 = 1289c [ 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 | | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1289c [ 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 TITAN FOS/BL ACQ/ 1.0 MIRROR 2230- MAP=COARSE 1 0.96S 1 1 GUID TOL 0.04" FIRMWAR 3309 BRIGHT=327700 SEQ 1-5 E FAINT=6554 NO GAP CYCLE 1 / 1-5 ONBOARD ACQ FOR 4- 5 ------------------------------------------------------------------------------------------------------------------------------------ 4 TITAN FOS/BL ACCUM 1.0 G270H 2230- 1 25.2M 50 2 1 GUID TOL 0.04" 3309 ------------------------------------------------------------------------------------------------------------------------------------ 4.05 TITAN FOS/BL ACCUM 1.0 G190H 1900 1 25.2M 20 2 1 GUID TOL 0.04" ------------------------------------------------------------------------------------------------------------------------------------ 4.1 TITAN FOS/BL ACQ 1.0 MIRROR 2230- 1 3.84S 1 1 GUID TOL 0.04" 3309 SEQ 4-4.1 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 5 TITAN FOC/96 IMAGE 512X512 F220W, 1 25.2M 20 2 1 GUID TOL 0.04" F231M ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1289c [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/FIRMWARE ACCUM ACQ IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters MAP=COARSE BRIGHT=327700 FAINT=6554 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category MINOR PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GUID TOL 0.04"; SEQ 1-5 NO GAP; CYCLE 1 / 1-5; ONBOARD ACQ FOR 4-5; GUID TOL 0.04" GUID TOL 0.04"; SEQ 4-4.1 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G270H G190H F220W,F231M ------------------------------------------------------------------------------------------------------------------------------------ Target Names TITAN ------------------------------------------------------------------------------------------------------------------------------------