Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5414 Report Date: 18-Jul-95:17:20 Version: ********** Check-in Date: ********** 1.Proposal Title: DAYGLOW EMISSION LINE PROFILES FROM THE OUTER PLANETS CYCLE4-MED ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GO Sub Category GIANT PLANETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone John T. Clarke UNIVERSITY OF MICHIGAN USA 313-747-3540 ------------------------------------------------------------------------------------ 7. Abstract Recent IUE observations of the H Ly alpha emission line profile from Jupiter's dayglow and aurora reveal a substantial line broadening, implying that the observed high brightness is due to resonant scattering of solar emission with a broad line rather than charged particle excitation. This may reflect highly energetic processes producing a 5-10 km/sec suprathermal population of H atoms in Jupiter's upper atmosphere, which in turn may be related to the unresolved question of the high exospheric temperatures of 400-1200 K detected on all 4 giant planets during the Voyager encounters. 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 provide a discriminant between the processes of resonant scattering and charged particle excitation. We propose to obtain high signal to noise H Ly alpha line profile measurements from Saturn, Uranus, and Neptune to resolve the questions about the excitation processes for the bright airglow emissions. ALL SATURN OBSERVATIONS HAVE BEEN MOVED TO A NEW PROPOSAL. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 7.70 par: 0 10. Num targs pri: 6 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. Real Time obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5414 PI: John T. Clarke Proposal Title: DAYGLOW EMISSION LINE PROFILES FROM THE OUTER PLANETS CYCLE4-MED ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John T. Clarke 2660 USA Lotfi Ben Jaffel 5436 FRANCE X Randall Gladstone 3440 USA Renee Prange 5448 FRANCE X Alfred Vidal-Madjar 5436 FRANCE X Hunter Waite 3440 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We request 6 dark orbit spectra, with two spectra each for Saturn and Uranus and one for Neptune. The Saturn observations will consist of center to limb scans with the GHRS LSA (echelle A at 1215.7 A), with scans E/W and N/S from the planet center to the limb. The scan across the north pole will be important to reveal any line broadening associated with the polar aurora, as has been observed on Jupiter, and the E/W scan will show the changing line shape with the increased slant column near the limb. The 2 arc sec LSA is somewhat smaller than Uranus (3.8 arc sec diameter) and Neptune (2.4 arc sec diameter), although it is filled by both planets, and planet- center spectra will be taken of each. In addition, one spectrum will be obtained near the limb of Uranus where the magnetic pole is presently rotating in and out of the field of view from the Earth. Since the rotational ephemeris for Uranus is insufficiently accurate to determine the longitude system today, we will have to take our chances on the location of any auroral emission near the pole. Since the emissions from Neptune are closer to the background brightness, planet and sky background spectra will be taken. Saturn can be acquired by blind offset from guide stars, and GHRS autonomous acquisitions of satellites will be used for offsets to Uranus and Neptune. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. As described above, we are also pursuing this program with IUE observa- tions of Jupiter, Saturn, and Uranus: Neptune is too faint for IUE at high resolution. The observations are limited by much lower sensitivity, and roughly a factor of two lower spectral resolution, of IUE compared with the GHRS echelle A and LSA. The existing IUE data with the SWP camera and small aperture at high dispersion are shown by 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 will allow us to obtain high quality H Ly alpha line profiles of regions on Saturn, and determine the full line shapes (including the important wings). With the 2 arc sec GHRS LSA we will also obtain sub-solar + auroral latitude spectra of Uranus with good sensitivity in the wings, and we expect to get a basic line width measurement of the fainter emission from Neptune. From our experience with IUE spectra at low signal to noise, we have determined that the H Ly alpha 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 RS of solar and IPM Ly alpha. Neptune is the one case where the emission is sufficiently faint that the line may be narrow, and we wish to make this observation for comparison with the other 3 planets. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. We need to minimize the sky background subtraction, which involves minimizing the geocoronal background Ly alpha emission by observing near opposition. We also need some minimum Doppler shift between the planetary and geocoronal emissions from observing near 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. This will allow us to separate spectrally the geoc. and planetary emissions. PLEASE NOTE: several parameters in the exposure list will need to be adjusted depending on the dates of observations, for Saturn and Uranus. PLEASE CONTACT THE PI WHEN THE WEEK OF OBSERVING IS SET to check this. The observation requires that the grating tilt should be kept same for the WAVE calibration as one of the scientific exposures in each group, for the targets, Saturn, Uranus, and Neptune. This means NO SPYBAL OPERATIONS SHOULD TAKE PLACE IN BETWEEN THE SCIENTIFIC EXPOSURES AND THE WAVE CALIBRATION. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. None. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. None. ------------------------------------------------------------------------------------ 9. Description of previous HST work. There are a total of 21 programs in cycles 1-3, resulting in (to date) nine publications. Several more publications are in the process of being submitted and/or reviewed. ------------------------------------------------------------------------------------ 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 Internet. Three Sun Sparcstations with IDL are presently being used for IUE and HST data reductions. 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 with this project. ------------------------------------------------------------------------------------ 11. Address Information Name: John T. Clarke Category: PI Institution: 2660 Address: AOSS Department 2455 Hayward City: Ann Arbor State: MI Zip Code: 481092143 Country: USA Telephone: 313-747-3540 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5414 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 | TARGET NAME: TITANIA-ACQ ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE TITANIA ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = URANUS, ACQ = 0.25 | STD = TITANIA | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF URANUS BETWEEN 300 330, | SEP OF OBERON TITANIA FROM EARTH | GT 10", SEP OF UMBRIEL TITANIA FROM | EARTH GT 10", SEP OF ARIEL TITANIA | FROM EARTH GT 10" | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V = 13.7 | ON-BOARD ACQUISITION OF TITANIA FOR | | OFFSET TO URANUS. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 4 | TARGET NAME: URANUS-CENTER ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET URANUS ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = URANUS, ACQ = 0.25 | | ------------------------------------------------------------------------------------------------------------------------------------ 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 ECH-A SPECTRUM OF H LY ALPHA 3 |W-LINE(1216) = 0.2 +/- 0.15 | LINE WHEN URANUS OLG = 300-330 | | DEGREES. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5414 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 5 | TARGET NAME: URANUS-AUR ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET URANUS ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = URANUS, ACQ = 0.25 | TYPE=POS_ANGLE, REF=NORTH, | ANG = 275., RAD=1.4 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF URANUS BETWEEN 300 330 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 8.0 | OBSERVE URANUS NEAR LIMB WHERE 2 |SURF-LINE(1216) = 3. +/- 1. E-12 | AURORAL EMISSION IS EXPECTED. GHRS 3 |W-LINE(1216) = 0.2 +/- 0.15 | ECH-A SPECTRUM OF H LY ALPHA LINE | | WHEN URANUS OLG = 300-330 DEGREES. | | NOTE: RAD DEPENDS ON DAY OF | | OBSERVATION. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 6 | TARGET NAME: TRITON-ACQ ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE TRITON ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = NEPTUNE, ACQ = 0.25 | STD = TRITON | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF NEPTUNE BETWEEN 300 330 | OLG OF NEPTUNE BETWEEN 30 60 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V = 13.5 | ON-BOARD ACQUISITION OF TRITON FOR | | OFFSET TO NEPTUNE. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5414 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 7 | TARGET NAME: NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = NEPTUNE, ACQ = 0.25 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF NEPTUNE BETWEEN 300 330 | OLG OF NEPTUNE BETWEEN 30 60 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 9.0 | OBSERVE NEPTUNE AT PLANET CENTER. 2 |SURF-LINE(1216) = 0.6 +/- 0.6 E-12 | GHRS ECH-A SPECTRUM OF H LY ALPHA 3 |W-LINE(1216) = 0.1 +/- 0.05 | LINE. NEPTUNE OLG = 300-330 OR 30- | | 60 DEGREES. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 8 | TARGET NAME: NEPTUNE-OFFSET-SKY ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = NEPTUNE | TYPE=POS_ANGLE, REF=NORTH, | ANG = 0, RAD=60 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF NEPTUNE BETWEEN 300 330 | OLG OF NEPTUNE BETWEEN 30 60 | ------------------------------------------------------------------------------------------------------------------------------------ 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 NEPTUNE. 3 |W-LINE(1216) = .04 +/- .02 | OFFSET NORTH BY 1 ARC MINUTE. ALSO | | GIVES SKY BACKGROUND FOR SATURN AND | | URANUS, SO PLEASE SCHEDULE #1-8 | | CLOSE IN TIME. | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5414 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4.1 TITANIA-ACQ HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 90S 1 2 ONBOARD ACQ FOR 5 GROUP 4.1-6.1 NO GAP SEQ 4.1-6 NO GAP CYCLE 4 / 4.1-9 Comments: ON-BOARD ACQ OF TITANIA WITH N2. WITH GHRS N2 - THEN OFFSET TO URANUS FOR ECH-A SPECTRA. I TAKE STEP-TIME = 10 SEC FOR 2000 COUNTS/DWELL PT. ------------------------------------------------------------------------------------------------------------------------------------ 4.2 TITANIA-ACQ HRS IMAGE 2.0 MIRROR-N2 1 350S 1 3 Comments: IMAGE OF TITANIA IN LSA AFTER CENTERING. EXPECT 250 COUNTS MAX. ------------------------------------------------------------------------------------------------------------------------------------ 5 URANUS- HRS ACCUM 2.0 ECH-A 1215.0 FP-SPLIT=STD 6 300S 10 2 1 DARK TIME / 5-6 CENTER STEP-PATT=9 300S STEP-TIME=1.0 DOPPLER=ON Comments: OBSERVE URANUS AT PLANET CENTER. GHRS ECH-A SPECTRUM OF H LY ALPHA LINE WHEN URANUS OLG = 300-330 DEGREES. ------------------------------------------------------------------------------------------------------------------------------------ 6 URANUS-AUR HRS ACCUM 2.0 ECH-A 1215.0 FP-SPLIT=STD 6 300S 10 2 1 STEP-PATT=9 300S STEP-TIME=1.0 DOPPLER=ON Comments: OBSERVE URANUS NEAR LIMB WHERE AURORAL EMISSION IS EXPECTED. GHRS ECH-A SPECTRUM OF H LY ALPHA LINE WHEN URANUS OLG = 300-330 DEGREES. NOTE: RAD DEPENDS ON DAY OF OBSERVATION. ------------------------------------------------------------------------------------------------------------------------------------ 6.1 WAVE HRS ACCUM SC2 ECH-A 1215.0 FP-SPLIT=STD 1 2M 50 1 1 CALIB FOR 6 STEP-PATT=9 120S PCS MODE G STEP-TIME=1.0 Comments: WAVELENGTH CALIBRATION FOR 5-6. NO SPYBAL SHOULD OCCURE BETWEEN LINE 6-6.1. ------------------------------------------------------------------------------------------------------------------------------------ 7.1 TRITON-ACQ HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE=3 1 90S 1 2 ONBOARD ACQ FOR 8 GROUP 7.1-9 NO GAP SEQ 7.1-8 NO GAP Comments: ON-BOARD ACQ OF TRITON WITH N2. WITH GHRS N2 - THEN OFFSET TO NEPTUNE FOR ECH-A SPECTRA. I TAKE STEP-TIME = 10 SEC FOR 2000 COUNTS/DWELL PT. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5414 [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 7.2 TRITON-ACQ HRS IMAGE 2.0 MIRROR-N2 1 350S 1 3 Comments: IMAGE OF TRITON IN LSA AFTER CENTERING. EXPECT 250 COUNTS MAX. ------------------------------------------------------------------------------------------------------------------------------------ 8 NEPTUNE HRS ACCUM 2.0 ECH-A 1215.0 FP-SPLIT=STD 5 600S 8 2 2 DARK TIME STEP-PATT=9 600S STEP-TIME=1.0 DOPPLER=ON Comments: OBSERVE NEPTUNE AT PLANET CENTER. GHRS ECH-A SPECTRUM OF H LY ALPHA LINE. NEPTUNE OLG = 300-330 OR 30- 60 DEGREES. NO SPYBAL SHOULD OCCURE BETWEEN LINE 8-8.1. ------------------------------------------------------------------------------------------------------------------------------------ 8.1 WAVE HRS ACCUM SC2 ECH-A 1215.0 FP-SPLIT=STD 1 2M 50 1 1 CALIB FOR 8 STEP-PATT=9 120S PCS MODE G STEP-TIME=1.0 Comments: WAVELENGTH CALIBRATION FOR 8-9. ------------------------------------------------------------------------------------------------------------------------------------ 9 NEPTUNE- HRS ACCUM 2.0 ECH-A 1215.0 FP-SPLIT=STD 6 300S 10 2 1 DARK TIME OFFSET-SKY STEP-PATT=9 300S STEP-TIME=1.0 DOPPLER=ON Comments: OBSERVE SKY BACKGROUND GEO AND IPM LY ALPHA EMISSIONS NEAR NEPTUNE. OFFSET NORTH BY 1 ARC MINUTE. ALSO GIVES SKY BACKGROUND FOR SATURN AND URANUS, SO PLEASE SCHEDULE #1-9 CLOSE IN TIME. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5414 [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=3 FP-SPLIT STEP-PATT STEP-TIME DOPPLER STEP-TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 7.70 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category GIANT PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 5; GROUP 4.1-6.1 NO GAP; SEQ 4.1-6 NO GAP; CYCLE 4 / 4.1-9; DARK TIME / 5-6 CALIB FOR 6; PCS MODE G ONBOARD ACQ FOR 8; GROUP 7.1-9 NO GAP; SEQ 7.1-8 NO GAP DARK TIME CALIB FOR 8; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 ECH-A ------------------------------------------------------------------------------------------------------------------------------------ Target Names TITANIA-ACQ URANUS-CENTER URANUS-AUR TRITON-ACQ NEPTUNE NEPTUNE-OFFSET-SKY ------------------------------------------------------------------------------------------------------------------------------------