Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3311c Report Date: 09-May-96:18:23 Version: ********** Check-in Date: ********** 1.Proposal Title: STRUCTURE AND COMPOSITION OF TITAN'S ATMOSPHERE: CYCLE 2 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/OS 1289 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 and near infrared imaging and with ultraviolet spectroscopy. The near infrared imaging includes both the CH 4 band at 8890A and the nearby continuum, with a very broad-band filter for the latter. These wavelengths were not covered by the previous Voyager imaging. The CH band images may show atmospheric structure not otherwise visible, 4 because of the high opacity at this wavelength. The continuum image may actually sample the surface of Titan because the opacity there may be much lower than at other accessible wavelengths. The ultraviolet imaging is to look for very high altitude atmospheric structure that might be associated with details of the ultraviolet spectroscopy (which will itself have not spatial resolution). The ultraviolet spectroscopy will include a search for discrete absorption features, including those of CO, as well as continuum Rayleigh scattering from the atmosphere. 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 3311c PI: John J. Caldwell Proposal Title: STRUCTURE AND COMPOSITION OF TITAN'S ATMOSPHERE: CYCLE 2 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John J. Caldwell YORK UNIVERSITY CANADA ------------------------------------------------------------------------------------ 3. Description of proposed observations. The observations include three images and two spectra. The first image will be used for interactive acquisition of the spectra. The spectrarequire the prior completion and assimilation of the SV test "Spectrograph RedLeak Test." ------------------------------------------------------------------------------------ 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. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. An interactive acquisition is probably necessary. Otherwise,there are no special scheduling requirements. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. There are no special requirements of these types. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The images 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, includingCO at 2060 A. 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, which is 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 expect to have access to a VAX computer from the engineering department at SUNY, to supplement the resources of the ST ScI. ------------------------------------------------------------------------------------ 13. Ultraviolet spectroscopy and both ultraviolet and near infrared imaging of Tital will be obtained. The imaging complements the Voyager data set, at different wavelengths, where the atmosphere is known to absorb very strongly (methane bands, uv) and where it may be somewhat transparent( between methane bands). The spectra will be analyzed for discrete absorptionfeatures (such as CO) and for continuum Rayleigh scattering, which has not yetbeen detected because of strong aerosol scattering. ------------------------------------------------------------------------------------ 11. Address Information Page 3 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 = 3311c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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: GANYMEDE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE GANYMEDE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = JUPITER | STD = GANYMEDE | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V=4.6, TYPE=G8V | 2 |F(2116)=9E-14 | 3 |F(2500)=5E-14 | | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3311c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 3 TITAN FOC/96 IMAGE 512X512 F220W, 4 30M 20 2 1 GUID TOL 0.05" F231M CYCLE 2 CONDITIONAL IF TAC OK ------------------------------------------------------------------------------------------------------------------------------------ 3.1 TITAN HRS ACCUM 2.0 G200M 2060 8 30M 20 3 1 GUID TOL 0.1" CYCLE 2 CONDITIONAL IF TAC OK ------------------------------------------------------------------------------------------------------------------------------------ 3.2 GANYMEDE HRS ACCUM 2.0 G200M 2060 2 30M 20 3 1 GUID TOL 0.1" CYCLE 2 CONDITIONAL IF TAC OK ------------------------------------------------------------------------------------------------------------------------------------ 5 TITAN FOS/BL ACCUM 1.0 G190H 1900 1 2H 27 3 1 GUID TOL 0.1" CYCLE 2 Comments: DEPENDS ON THE SV "SPECTROGRAPH RED LEAK TEST" PROP NO. 1343. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3311c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 HRS FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category MINOR PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GUID TOL 0.05"; CYCLE 2; CONDITIONAL IF TAC OK GUID TOL 0.1"; CYCLE 2; GUID TOL 0.1"; CYCLE 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F220W,F231M G200M G190H ------------------------------------------------------------------------------------------------------------------------------------ Target Names TITAN GANYMEDE ------------------------------------------------------------------------------------------------------------------------------------