Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3511c Report Date: 09-May-96:18:40 Version: ********** Check-in Date: ********** 1.Proposal Title: H LY ALPHA DAYGLOW EMISSION LINE PROFILES FROM THE OUTER PLANETS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GO 3511 Sub Category GIANT PLANETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone John T. Clarke UNIVERSITY OF MICHIGAN USA 313-747-3540 ------------------------------------------------------------------------------------ 7. Abstract One of the outstanding scientific questions about the outer planets following the Voyager tour is why the upper atmospheres have bright FUV airglow emissions and very high exospheric temperatures of 400 - 1200 K on the 4 planets. IUE observations of Jupiter's H Ly alpha emission line profile have shown that the equatorial lines are broad, and can be fit by the inclusion of a velocity distribution in addition to thermal motions (although the physical process leading to this additional component has not been identified). It is clear that if the bright H Ly alpha emissions from the outer planets are due mainly to resonant scattering of solar and interplanetary emissions, as observed on Jupiter and Saturn from long term correlations with the solar Ly alpha flux, then the lines from all 4 planets must be broad to explain the observed high albedos. The H Ly alpha lineshapes certainly provide a discriminant between processes of resonant scattering and charged particle excitation. We propose to obtain good signal H Ly alpha line profile measurements at the center and limb of Jupiter, and single sub-solar point measurements from Saturn and Uranus, to resolve the questions about the excitation processes and to explore the possibility that the upper atmospheric line broadening process is also the source of the observed thermospheric heating. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 5.93 par: 0 10. Num targs pri: 6 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 3511c PI: John T. Clarke Proposal Title: H LY ALPHA DAYGLOW EMISSION LINE PROFILES FROM THE OUTER PLANETS ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Prof. John T. Clarke UNIVERSITY OF MICHIGAN USA Randall Gladstone UNIVERSITY OF CALIFORNIA, USA BERKELEY Lotfi Ben Jaffel UNIVERSITY OF ARIZONA USA Renee Prange INSTITUT D'ASTROPHYSIQUE FRANCE X SPATIALE Alfred Vidal-Madjar OBSERVATOIRE DE PARIS FRANCE X ------------------------------------------------------------------------------------ 2. Scientific Justification. ------------------------------------------------------------------------------------ 3. Description of proposed observations. We require 6 dark orbits for this program, with 3 orbits for Jupiter (bulge center, bulge limb, and mid-latitudes), one each for Saturn and Uranus, and one geocoronal/interplanetary H Ly alpha sky background. The Jupiter observations will consist of one dark orbit integration each pointing the GHRS SSA with G160M at 1) Jupiter's equatorial "Ly alpha bulge" region on the central meridian, 2) the bulge longitudes (equator) at 70 degrees from the central meridian toward the sunlit limb, and 3) midlatitudes on the central meridian. Since there is no corresponding bulge region on Saturn, we can observe any longitude and will center the aperture between the rings and north pole (roughly +20 degrees latitude). The 0.25 arc sec GHRS SSA need only be centered on the 3.8 arc sec Uranus disk to within roughly 1 arc sec, although post-observation pointing information to within better than 1/2 arc sec is desired. Since the emissions from Saturn and Uranus are closer to the background brightness, planet and sky background spectra will be taken in these cases. Jupiter and Saturn can be acquired by blind pointing on coarse track, and GHRS autonomous acquisition will be used for Uranus, also on coarse track. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. We are also pursuing this program with IUE observations of Jupiter, and have applied to observe Saturn and Uranus: Neptune is too faint for IUE at high resolution. These observations are limited by the lower sensitivity, and roughly a factor of two lower spectral resolution, of IUE compared with the GHRS G160M and SSA. The existing IUE data with the SWP camera and small aperture at high dispersion have been published (Clarke et al. 1991). Longer exposures are possible with IUE, but Jupiter's rotation of 36 degrees/hour limits observations of specific longitude regions to 2-3 hours. The GHRS spectral capabilities should allow us to obtain high quality H Ly alpha emission line profiles of discrete regions on Jupiter, and determine the full line shapes (including the wings) on those planets. With the .25 arc sec GHRS SSA we will also obtain a sub-solar point spectrum of Uranus, with good sensitivity to the overall line width. From our experience with IUE spectra at low signal to noise, we have determined that the H Ly alpha line profile of Jupiter is very broad, and the high Ly alpha albedos of Saturn and Uranus require similarly broad lines if the dominant emission process is resonant scattering of solar and IPM Ly alpha. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. We desire to minimize the geocoronal background Ly alpha emission, and also to obtain the maximum Doppler shifts between the planetary and geocoronal emissions. This is accomplished by observing when the planet is roughly 30-60 degrees from the anti-solar point, so that the combined Earth and HST orbital motions of 38 km/sec have large components along the line of sight during the dark portion of the HST orbit when the background is minimal. A preferred Jupiter longitude range is desired for those observations, but there are no longitude requirements for the other planets. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. The only specific calibrations for this program that are not generally available will be a flat field at the same y-deflection as the observations, and an SSA G160M scattered light and line profile measurement using the on- board Pt- Ne calibration lamps. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The GHRS data will be reduced at the University of Michigan using standard programs obtained from the ST ScI or GHRS team. The analysis of the data will involve shifting and co-adding the individual FP-split segments, applying any flat field, and measuring and subtracting the background geocoronal and IPM emissions. The IPM emissions will be largely Doppler-shifted off the planetary lines, and we will schedule the observations when the planetary lines have nearly the largest possible Doppler shift from the geocoronal emission (see above). We will then compare models for the line profiles convolved with the GHRS point spread function (as in Figure 2) with the data from each planet: R. Gladstone and L. Ben Jaffel will take the lead in modeling the data, and both have modeling codes ready for use. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. None. ------------------------------------------------------------------------------------ 9. Description of previous HST work. 1. GO 2602 - "The Excitation of the Atmospheres of Planetary Satellites", J. Clarke PI - unrelated. 2. GO 2603 - "Parallel Observations of H Ly alpha Emission from the Local ISM", J. Clarke PI - related for sky background. 3. GO 2393 - "D/H Ratio of Venus and Mars from Lyman alpha Emission", J. Clarke Co-I - unrelated. 4. GO 2625 - "Excitation Processes for the Outer Planet UV Emissions", J. Clarke Co-I - possibly related scientifically. 5. GTO 1269 - "Far UV Observations of the Giant Planets", A. Vidal-Madjar Co-I - related. 6. GO 2727 - "Search for Exogenous Water in Saturn's Atmosphere: A Critical Test for Ring Erosion Theories", R. Prange PI - unrelated. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Complete computing facilities are in place and available within the Space Physics Research Laboratory at the University of Michigan for use on this project. Two VAX 750's and a VAX 8600 are accessible via a local area network, in addition to the Michigan network MERIT, SPAN, and NASA Internet. A SUN 4/110 workstation with IDL is presently being used for IUE and HST data reductions, and a Sparcstation IPX with IDL is being procured under cycle 1 GO funding. All Co-Investigators also have complete computer facilities available at their institutions for use on this project, and graduate students are available at all institutions for assistance on this project. ------------------------------------------------------------------------------------ 11. Address Information Page 4 Name: JOHN T. CLARKE Category: PI Institution: UNIVERSITY OF MICHIGAN Address: AOSS DEPT. City: ANN ARBOR State: MI Zip Code: 481092143 Country: USA Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3511c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: JUPITER-CML ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET JUPITER FEATURE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = JUPITER, ACQ = 2. | TYPE=TORUS,POLE_LAT=90, | RAD=42.,LAT=0,LONG=0 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF JUPITER BETWEEN 30 60, | CML OF JUPITER FROM EARTH | BETWEEN 50 150 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 5.3 | OBSERVE JUPITER "BULGE" REGION AT 50 2 |SURF-LINE(1216) = 2. +/- 1. E-11 | -150 DEG. SYSTEM III LONGITUDE AND 3 |W-LINE(1216) = 0.15 +/- 0.1 | MAGNETIC EQUATOR ON CENTRAL | | MERIDIAN. GHRS G160M SPECTRUM OF LY | | ALPHA LINE PROFILE WITH SSA. OLG = | | 30-60 FOR TARGETS 1-3 MEANS ROUGHLY | | 28 FEB. TO 27 MARCH 1993. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: JUPITER-LIMB ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET JUPITER FEATURE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = JUPITER, ACQ = 2. | TYPE=TORUS,POLE_LAT=90, | RAD=42.,LAT=0,LONG=290 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF JUPITER BETWEEN 30 60, | CML OF JUPITER FROM EARTH | BETWEEN 340 80 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 5.3 | OBSERVE JUPITER "BULGE" REGION AT 50 2 |SURF-LINE(1216) = 2. +/- 1. E-11 | -150 DEG. SYSTEM III LONGITUDE AT 3 |W-LINE(1216) = 0.15 +/- 0.1 | MAGNETIC EQUATOR AND 70 DEG. FROM | | CENTRAL MERIDIAN TOWARD APPROACHING | | SUNLIT LIMB. GHRS G160M SPECTRUM OF | | LY ALPHA LINE PROFILE WITH SSA. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3511c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 | TARGET NAME: JUPITER-MIDLATITUDE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET JUPITER FEATURE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = JUPITER, ACQ = 2. | TYPE=TORUS,POLE_LAT=90, | RAD=42.,LAT=+30,LONG=0 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF JUPITER BETWEEN 30 60, | CML OF JUPITER FROM EARTH | BETWEEN 150 50 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 5.3 | OBSERVE JUPITER MIDLATITUDES AT 150- 2 |SURF-LINE(1216) = 2. +/- 1. E-11 | 50 DEG. SYSTEM III LONGITUDE AT +30 3 |W-LINE(1216) = 0.15 +/- 0.1 | DEG. LATITUDE ON CENTRAL MERIDIAN. | | GHRS G160M SPECTRUM OF LY ALPHA LINE | | PROFILE WITH SSA. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 4 | TARGET NAME: SATURN ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET SATURN FEATURE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = SATURN, ACQ = 2. | TYPE = CARTO, LAT = +20., LONG=0. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF SATURN BETWEEN 300 330 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 7.0 | OBSERVE SATURN AT +20 DEG. LATITUDE 2 |SURF-LINE(1216) = 3. +/- 1. E-12 | ON CENTRAL MERIDIAN, ANY LONGITUDE. 3 |W-LINE(1216) = 0.15 +/- 0.1 | GHRS G160M SPECTRUM OF H LY ALPHA | | LINE PROFILE WITH SSA. OLG = 300- | | 330 FOR SATURN MEANS ROUGHLY 5 SEPT. | | TO 4 OCT. 1993. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3511c [ 7] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 5 | TARGET NAME: URANUS ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET URANUS CENTER ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = URANUS, ACQ = 1. | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF URANUS BETWEEN 300 330 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 8.0 | OBSERVE URANUS AT PLANET CENTER. 2 |SURF-LINE(1216) = 3. +/- 1. E-12 | GHRS G160M SPECTRUM OF H LY ALPHA 3 |W-LINE(1216) = 0.2 +/- 0.15 | LINE PROFILE WITH SSA. OLG = 300- | | 330 FOR URANUS MEANS ROUGHLY 6 | | AUGUST TO 6 SEPT. 1993. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 6 | TARGET NAME: URANUS-OFFSET ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET URANUS OFFSET ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = URANUS | TYPE=POS_ANGLE, REF=NORTH, | ANG = 0, RAD=60 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF URANUS BETWEEN 300 330 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 8.0 | OBSERVE SKY BACKGROUND GEO. AND IPM 2 |SURF-LINE(1216) = 3. +/- 2. E-12 | LY ALPHA EMISSIONS NEAR URANUS. 3 |W-LINE(1216) = .04 +/- .02 | OFFSET NORTH BY 1 ARC MINUTE. THIS | | WILL PROVIDE BACKGROUND SUBTRACTION | | FOR BOTH SATURN AND URANUS DATA, SO | | PLEASE SCHEDULE TARGETS 4-6 CLOSE IN | | TIME. | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3511c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 JUPITER-CML HRS ACCUM 0.25 G160M 1223.0 FP-SPLIT=STD 3 700S 2 1 CYCLE 2 / 1-6 STEP-PATT=DEF PCS MODE C / 1-5 STEP-TIME=1.0 DARK-TIME /1-6 DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ 2 JUPITER- HRS ACCUM 0.25 G160M 1223.0 FP-SPLIT=STD 3 700S 2 1 LIMB STEP-PATT=DEF STEP-TIME=1.0 DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ 3 JUPITER- HRS ACCUM 0.25 G160M 1223.0 FP-SPLIT=STD 3 700S 3 1 GROUP 1-3 WITHIN MIDLATITUDE STEP-PATT=DEF 14D STEP-TIME=1.0 DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ 4 SATURN HRS ACCUM 0.25 G160M 1223.0 FP-SPLIT=STD 3 800S 2 1 STEP-PATT=DEF STEP-TIME=1.0 DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ 5 URANUS HRS ACCUM 0.25 G160M 1223.0 FP-SPLIT=STD 3 800S 2 1 SEQ 5-6 NOGAP STEP-PATT=DEF STEP-TIME=1.0 DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ 6 URANUS- HRS ACCUM 0.25 G160M 1223.0 FP-SPLIT=STD 3 800S 2 2 PCS MODE G OFFSET STEP-PATT=DEF STEP-TIME=1.0 DOPPLER=ON ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3511c [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT STEP-PATT STEP-TIME=1.0 DOPPLER STEP-TIME ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 5.93 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category GIANT PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 2 / 1-6; PCS MODE C / 1-5; DARK-TIME /1-6; GROUP 1-3 WITHIN 14D SEQ 5-6 NOGAP PCS MODE G ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names JUPITER-CML JUPITER-LIMB JUPITER-MIDLATITUDE SATURN URANUS URANUS-OFFSET ------------------------------------------------------------------------------------------------------------------------------------