9745( 5) - 10/02/03 14:55 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9745 Version: 5 Check-in Date: 02-Oct-2003 14:54:25 1.Proposal Title: From molecules to aerosols: observing the haze creation process during Titan's polar summer ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dr. Mark T. Lemmon Texas A & M Research Foundation CoI: Mr. Peter H. Smith University of Arizona N CoI: Dr. Ralph D. Lorenz University of Arizona N ------------------------------------------------------------------------------------ 5. Abstract Our Cycle 11 observations of Titan at southern summer solstice reveal unexpected complexity and an opportunity for science that has not previously been possible. Titan currently has a polar hood below 65 degrees S. The polar hood is dark in the visible relative to the southern mid-latitudes, as is Titan's northern hemisphere. In the UV and near-IR, the hood is spectrally distinct from the better-known north- south asymmetry, indicating a different formation mechanism. The nature of the relation between the southern summer hood and the northern spring equinox polar hood observed by Voyager is uncertain. We propose a set of ultraviolet and supporting observations to demonstrate the nature of temporal changes in the hood and to look for expected stratospheric absorbing gasses. The gasses are precursors to Titan's aerosols; the polar hood may be an early stage of aerosol evolution. Our observations will provide important constraints on the chemistry and dynamics of Titan's stratosphere at summer solstice. The chance to follow-up our observations of the polar hood will allow us to assess the processes and changes that are occurring now, so that Cassini observations of the polar regions will not need to be interpreted in isolation from seasonal context. ------------------------------------------------------------------------------------ 9745( 5) - 10/02/03 14:55 - [ 2] Observations Description ------------------------ ACS: near 2D phase angle before opposition for consistency with 2002 observations. Orbit 1: GSA, then single ACS/SBC image with F165LP filter for expected S/N of 6. Orbits 2-3: re-acquisition, followed by CRSPLIT exposure with F220W, followed by 4-point dither set using F250W, F330W, F435W, and F475W. The dither set is spread over 2 orbits. After the dither set, CRSPLIT images are acquired with F502N, F550M, and F892N. Any exposure times can be modified up or down to fit different visibility periods. STIS: the observations are assumed to be near opposition based on the narrow ORIENT requirement (51+- 5, or 231+-5). After acquisition (using parameters that have been used previously), the first orbit is used for a single spectrum oriented to Titan's north-south axis with G230L, the NUV MAMA, and the 0.5 arcsec slit. The second orbit has a dither with G430L starting at the center of flux and moving outward. No recenter is needed due to symmetry. After that pattern, a dither with G750L and higher sampling density is used, also from the center outward. Any change in exposure time should be applied first to the G230L or G430L exposures, as needed. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9745( 5) - 10/02/03 14:55 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: TITAN-PHASE-2 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Satellite Titan ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=SATURN | STD=TITAN | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | PHASE OF TITAN FROM EARTH BETWEEN 0.0 | 2.1 | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 8.3+/-0.3 | SURF(U) = 9.8 | SURF(B) = 9.1 | SURF(V) = 7.8 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: TITAN-ANY ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Satellite Titan ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=SATURN | STD=TITAN | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 8.3+/-0.3 | SURF(U) = 9.8 | SURF(B) = 9.1 | SURF(V) = 7.8 | | ------------------------------------------------------------------------------------------------------------------------------------ 9745( 5) - 10/02/03 14:55 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-PERP-TO-SLIT Pattern_Purpose MOSAIC Number_Of_Points 4 Point_Spacing 0.1 Coordinate_Frame POS-TARG Pattern_Orient 0.0 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type STIS-PERP-TO-SLIT Pattern_Purpose MOSAIC Number_Of_Points 7 Point_Spacing 0.05 Coordinate_Frame POS-TARG Pattern_Orient 0.0 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.15 Coordinate_Frame POS-TARG Pattern_Orient 19.89 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9745( 5) - 10/02/03 14:55 - [ 5] Visit: 01 Visit Priority: Visit Requirements: PCS MODE FINE SCHED 70% BEFORE 05-JAN-2004:00:00:00 On Hold Comments: Additional Comments: Can waive the BEFORE requirement if needed, but partially compromises comparison with 2002 data. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TITAN-PHASE ACS/HR ACCUM HRC F220W CR-SPLIT=3 1 744 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 2 TITAN-PHASE ACS/HR ACCUM HRC F475W CR-SPLIT=NO 1 20 S PATTERN 3 2-5 -2 C ------------------------------------------------------------------------------------------------------------------------------------ 3 TITAN-PHASE ACS/HR ACCUM HRC F435W CR-SPLIT=NO 1 20 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 4 TITAN-PHASE ACS/HR ACCUM HRC F330W CR-SPLIT=NO 1 170 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 5 TITAN-PHASE ACS/HR ACCUM HRC F250W CR-SPLIT=NO 1 300 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 6 TITAN-PHASE ACS/HR ACCUM HRC F502N CR-SPLIT=2 1 120 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 7 TITAN-PHASE ACS/HR ACCUM HRC F658N CR-SPLIT=2 1 80 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 8 TITAN-PHASE ACS/HR ACCUM HRC F550M CR-SPLIT=2 1 20 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 9 TITAN-PHASE ACS/HR ACCUM HRC F892N CR-SPLIT=2 1 190 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ 10 TITAN-PHASE ACS/SB ACCUM SBC F165LP 1 2600 S -2 C ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 01 1 none none none 1 1 tbd 01 1 none none none 2 1 tbd 01 1 none none none 3 1 tbd 01 2 1 none none none 1 tbd 9745( 5) - 10/02/03 14:55 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 01 2 2 none none none 1 tbd 01 2 3 none none none 2 tbd 01 2 4 none none none 2 tbd 01 3 1 none none none 1 tbd 01 3 2 none none none 1 tbd 01 3 3 none none none 2 tbd 01 3 4 none none none 2 tbd 01 4 1 none none none 1 tbd 01 4 2 none none none 1 tbd 01 4 3 none none none 2 tbd 01 4 4 none none none 2 tbd 01 5 1 none none none 1 tbd 01 5 2 none none none 2 tbd 01 5 3 none none none 2 tbd 01 5 4 none none none 2 tbd 01 6 none none none 1 2 tbd 01 6 none none none 2 2 tbd 01 7 none none none 1 2 tbd 01 7 none none none 2 2 tbd 01 8 none none none 1 2 tbd 01 8 none none none 2 3 tbd 01 9 none none none 1 3 tbd 01 9 none none none 2 3 tbd 01 10 none none none none 4 tbd 9745( 5) - 10/02/03 14:55 - [ 7] Visit: 02 Visit Priority: Visit Requirements: SCHED 100% ORIENT 46.0D TO 56.0 D ORIENT 226.0D TO 236.0 D On Hold Comments: Additional Comments: Can open orientation constraints if need -- please consult PI first. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TITAN-ANY STIS/C ACQ F28X50L MIRROR CHECKBOX=9,ACQTYPE=DIFFUSE, 1 0.5 S CD P DIFFUSE-CENTER=GEOMETRIC-CENTER ------------------------------------------------------------------------------------------------------------------------------------ 2 TITAN-ANY STIS/N ACCUM 52X0.5 G230L 2376 1 2040 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 TITAN-ANY STIS/C ACCUM 52X0.1 G430L 4300 GAIN=1,CR-SPLIT=2,SIZEAXIS2=128 1 195 S PATTERN 1 3 CD ------------------------------------------------------------------------------------------------------------------------------------ 4 TITAN-ANY STIS/C ACCUM 52X0.1 G750L 7751 GAIN=1,CR-SPLIT=2,SIZEAXIS2=256 1 120 S PATTERN 2 4 CD ------------------------------------------------------------------------------------------------------------------------------------ 5 CCDFLAT STIS/C ACCUM 52X0.1 G750L 7751 2 DEF CD ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 02 1 none none none none 1 tbd 02 2 none none none none 1 tbd 02 3 1 none none 1 2 tbd 02 3 1 none none 2 2 tbd 02 3 2 none none 1 2 tbd 02 3 2 none none 2 2 tbd 02 3 3 none none 1 2 tbd 02 3 3 none none 2 2 tbd 02 3 4 none none 1 2 tbd 02 3 4 none none 2 2 tbd 02 4 1 none none 1 2 tbd 02 4 1 none none 2 2 tbd 02 4 2 none none 1 2 tbd 02 4 2 none none 2 2 tbd 02 4 3 none none 1 2 tbd 02 4 3 none none 2 2 tbd 02 4 4 none none 1 2 tbd 02 4 4 none none 2 2 tbd 02 4 5 none none 1 2 tbd 9745( 5) - 10/02/03 14:55 - [ 8] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 02 4 5 none none 2 2 tbd 02 4 6 none none 1 2 tbd 02 4 6 none none 2 2 tbd 02 4 7 none none 1 2 tbd 02 4 7 none none 2 2 tbd 02 5 none none 1 none 2 tbd 02 5 none none 2 none 2 tbd 9745( 5) - 10/02/03 14:55 - [ 9] Summary Form for Proposal 9745 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures HRC SBC F28X50LP 52X0.5 52X0.1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/HRC ACS/SBC STIS/CCD STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=3 CR-SPLIT=NO CR-SPLIT=2 DIFFUSE-CENTER=GEOMETRIC-CENTER SIZEAXIS2=128 SIZEAXIS2=256 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE SCHED 70% BEFORE 05-JAN-2004 00 00 00 PATTERN 3 2-5 SCHED 100% ORIENT 46.0D TO 56.0 D ORIENT 226.0D TO 236.0 D PATTERN 1 3 PATTERN 2 4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F220W F475W F435W F330W F250W F502N F658N F550M F892N F165LP MIRROR G230L G430L G750L ------------------------------------------------------------------------------------------------------------------------------------ Target Names TITAN-PHASE-2 TITAN-ANY CCDFLAT ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2376 4300 7751 ------------------------------------------------------------------------------------------------------------------------------------