Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4198c Report Date: 09-May-96:19:24 Version: ********** Check-in Date: ********** 1.Proposal Title: DO NEPTUNE AND PLUTO HAVE RINGS? PART 2 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/HSP 4076 Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Robert C. Bless WISCONSIN, UNIVERSITY OF USA 608-262-1715 ------------------------------------------------------------------------------------ 7. Abstract The origin of planetary ring systems remains unknown. One common property of the known ringed planets--Jupiter, Saturn, and Uranus--is that each possesses a regular satellite system, which would point to a close connection between the formation of rings and satellites. However, the dynamical lifetimes of several important features in Saturn's are short, which would lead to the conclusion that these rings are young. Continuing this line of reasoning, one would conclude that rings are not formed concurrently with planets--perhaps the formation of rings depends on encounters of planets with small bodies, or other random events: ring systems come and go. The discovery of ring systems around Neptune and/or Pluto would shift opinion toward this latter view, while the lack of detectable rings would greatly strengthen their apparent connection with regular satellite systems. The August, 1989 Voyager encounter with Neptune discovered complete rings with shepherd satellites, ------------------------------------------------------------------------------------ 8. Scientific Key Words: NEPTUNE, PLUTO, PLANETARY RINGS, OCCULTATIONS, RING IMAGING ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.58 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. Real Time obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4198c PI: Robert C. Bless Proposal Title: DO NEPTUNE AND PLUTO HAVE RINGS? PART 2 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Edward L. Robinson TEXAS, UNIVERSITY OF USA Robert C. Bless WISCONSIN, UNIVERSITY OF USA G. W. Van Citters NATIONAL SCIENCE FOUNDATION USA Joseph F. Dolan NASA, GODDARD SPACE FLIGHT USA CENTER Richard L. White SPACE TELESCOPE SCIENCE USA INSTITUTE James L. Elliot MASSACHUSETTS INSTITUTE OF USA TECHNOLOGY ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our ring search, for both Neptune and Pluto, will consist of occultations of opportunity, chosen to probe the equatorial plane of the planet (where rings are most likely to be). We plan to identify those occultations of sufficient signal- to-noise ratio to achieve the goals outlined in Section 2. Each observation will require (i) an onboard acquisition, (ii) a scan of about 10 to 20 arcseconds along the track that the object will follow relative to the occulting body, and (iii) a time series run on the object with whatever filter- aperture combination that is chosen for the observation. For some occultations to be observed in the far UV, prior multi-filter photometry of the object will be necessary in order to determine the most appropriate filter to use for the occultation. The default filter set is F750W/F320N. For now, we shall assume that the calibration and observation time will require 40 minutes for Pluto and 50 minutes for Neptune. Cycle 1: all predicted ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. For occultations, we can achieve a much better signal-to-noise ratio than would be possible from the ground for the following reasons: (i) the greatly improved photometric stability of ST photometry; (ii) our ability to reject background light from the occulting object by employing small focal plane apertures; and (iii) the absence of scintillation noise, which has strong components at frequencies comparable to the occultation timescale. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. A prior scan over 10 - 20 arc-seconds is needed to map the scattered light field, which is needed for the data reduction. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data will be reduced and analyzed at MIT with the DEC5000 belonging to the planetary astronomy group. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Data reduction and analysis will be supported on computer facilities at MIT. ------------------------------------------------------------------------------------ 13. Ring systems around Pluto will be searched for and the ring system around Neptune will be probed by stellar occultation observations with the HSP. The presence or absence of ring systems around these planets will be indicative of whether regular satellite systems are necessary for the formation of planetary rings. Page 3 ------------------------------------------------------------------------------------ 11. Address Information Name: ROBERT C. BLESS Category: PI Institution: UNIVERSITY OF WISCONSIN Address: DEPARTMENT OF ASTRONOMY City: MADISON State: WI Zip Code: 53706 Country: USA Telephone: 608-262-1715 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: JAMES L. ELLIOT Category: CON Institution: MASSACHUSETTS INSTITUTE OF TECHNO Address: BLDG. 54-422 City: CAMBRIDGE State: MA Zip Code: 02139 Country: USA Telephone: 617-253-6308 Telex (or e-mail): 921473 MIT CAM ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4198c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 13 N63 STAR TO BE OCCULTED BY PLATE-ID = 068E, J2000 BKG 1 V = 13.8 +/- 0.5 NEPTUNE. RA = 19H 13M 20.049S +/- CLOSE APPROACH AT 18- 0.03", NOV-92:08:00 DEC = -21D 40' 36.71" +/- 0.06" Comments: STAR POSITION WILL BE UPDATED BEFORE OBSERVATION IS PERFORMED. CONTACT: AMANDA S. BOSH, MIT SOLAR ELONG 51D ------------------------------------------------------------------------------------------------------------------------------------ 14 N63-OFFSET OFFSET TARGET FOR N63 PLATE-ID = 068E, J2000 1 B = 13.38 +/- 0.54 GSC6308- RA = 19H 13M 20.133S +/- 02241 0.03", DEC = -21D 41' 52.29" +/- 0.08" Comments: STAR POSITION WILL BE UPDATED BEFORE OBSERVATION IS PERFORMED. CONTACT: AMANDA S. BOSH, MIT ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 4198c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 19 | TARGET NAME: NEPTUNE-CENTER ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = NEPTUNE, ACQ = 0.1 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V = 7.8 +/- 0.5 | ACQUISITION TARGET FOR BACKGROUND | | SCANS | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 20 | TARGET NAME: N63-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = NEPTUNE | TYPE = POS_ANGLE, | RAD = 4.2, | ANG = 93.5, | REF = NORTH | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | | | FOR USE IN A SCAN OF BACKGROUND | | LEVELS ALONG THE PATH OF THE | | OCCULTED STAR | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4198c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 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 DEFINE # HSP/ ACQ 1 1S 1 1 ONBRD- VIS ACQ ------------------------------------------------------------------------------------------------------------------------------------ 6 DEFINE # HSP/ SPLIT 1.0 F750W/ # 1 1S 1 1 SPATIAL SCAN BACK- PMT/ F320N SCAN VIS ------------------------------------------------------------------------------------------------------------------------------------ 7 DEFINE # HSP/ SPLIT 1.0 F750W/ # 1 1M 1 1 CRIT OBS RING- PMT/ F320N OCC VIS ------------------------------------------------------------------------------------------------------------------------------------ 20 USE NEPTUNE- X4 ONBOARD ACQ FOR ONBRD- CENTER 20.01 ACQ SEQ 20.00 - 20.01 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 20.01 USE N63- SAMPLE- X107 SEQ 20.01 - 20.03 BACK- BACKGROUND TIME=0.05 GROUP 20.01 - SCAN PRECISION=HIGH 20.04 WITHIN 9H DATA-FORMAT=ALL CYCLE 2/20.00 - PMT-ANALOG=1000 20.28 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 20.02 USE N63- SAMPLE- X107 BACK- BACKGROUND TIME=0.05 SCAN PRECISION=HIGH DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 20.03 USE N63- SAMPLE- X107 BACK- BACKGROUND TIME=0.05 SCAN PRECISION=HIGH DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 20.04 USE N63-OFFSET X40 ONBOARD ACQ FOR ONBRD- 20.10 - 20.28 ACQ SEQ 20.04 - 20.10 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 20.1 USE N63 SAMPLE-TIME=0.1 X50 AT 18-NOV-92:07:11 RING- PRECISION=HIGH +/- 1M OCC DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 Comments: END EXPOSURE AT 18-NOV- 92:08:35. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4198c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 20.25 USE NEPTUNE- X4 ONBOARD ACQ FOR ONBRD- CENTER 20.26 ACQ SEQ 20.25 - 20.26 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 20.26 USE N63- SAMPLE- X107 SEQ 20.26 - 20.28 BACK- BACKGROUND TIME=0.05 GROUP 20.10 - SCAN PRECISION=HIGH 20.28 WITHIN 9H DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 20.27 USE N63- SAMPLE- X107 BACK- BACKGROUND TIME=0.05 SCAN PRECISION=HIGH DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 20.28 USE N63- SAMPLE- X107 BACK- BACKGROUND TIME=0.05 SCAN PRECISION=HIGH DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ Scan Paramters Form Proposal ID: 4198c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 20.01, 20.03, 20.26, FGS Scan: CONTINUOUS Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 30.5000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0750 PA of first scan line (degrees) 263.500 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 0. Width Offset (arc-sec): 0. ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 20.02, 20.27 FGS Scan: CONTINUOUS Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 2.0000 Scan length (arc-secs): 30.5000 Angle between sides (degrees) 90.00 Number of lines: 3 Scan rate (arc-sec/sec): 0.0750 PA of first scan line (degrees) 263.500 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 0. Width Offset (arc-sec): 1.0000 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4198c [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HSP/VIS HSP/PMT/VIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ SPLIT ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SAMPLE-TIME PRECISION DATA-FORMAT PMT-ANALOG VIS-ANALOG ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HSP ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.58 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SPATIAL SCAN; CRIT OBS; ONBOARD ACQ FOR 20.01; SEQ 20.00 - 20.01 NO GAP; SEQ 20.01 - 20.03; GROUP 20.01 - 20.04 WITHIN 9H; CYCLE 2/20.00 - 20.28; ONBOARD ACQ FOR 20.10 - 20.28; SEQ 20.04 - 20.10 NO GAP; AT 18-NOV-92 07 11 +/- 1M; ONBOARD ACQ FOR 20.26; SEQ 20.25 - 20.26 NO GAP; SEQ 20.26 - 20.28; GROUP 20.10 - 20.28 WITHIN 9H; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F750W/F320N ------------------------------------------------------------------------------------------------------------------------------------ Target Names N63 N63-OFFSET GSC6308-02241 NEPTUNE-CENTER N63-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------