8876( 14) - 08/08/00 08:18 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8876 Version: 14 Check-in Date: 08-Aug-2000 08:17:36 1.Proposal Title: Does Comet Linear Have a Nucleus? ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/DD 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Harold Weaver The Johns Hopkins University CoI: Dr. Gian-Paolo Tozzi Arcetri Observatory N CoI: Dr. Donald Yeomans Jet Propulsion Laboratory N CoI: Dr. Zdenek Sekanina Jet Propulsion Laboratory N CoI: Prof. Michael A'Hearn University of Maryland, College Park N CoI: Prof. Claude Arpigny Universite de Liege N CoI: Dr. Michael Combi University of Michigan N CoI: Prof. Paul Feldman The Johns Hopkins University N CoI: Dr. Michel Festou Observatoire Midi-Pyrenees N CoI: Dr. Michael Keesey Jet Propulsion Laboratory N CoI: Dr. Philippe Lamy Laboratoire d'Astronomie Spatiale N CoI: Dr. Brian Marsden Smithsonian Astrophysical Observatory N CoI: Dr. Zdenek Sekanina Jet Propulsion Laboratory N CoI: Dr. Imre Toth Konkoly Observatory N ------------------------------------------------------------------------------------ 5. Abstract The nucleus of Comet LINEAR (C/1999 S4) has reportedly disintegrated into a cloud of dust during the past week (Kidger, IAUC 7467, 27 July 2000). While there is little doubt that a major disruption event took place recently, a major unresolved issue is whether the comet left behind a remnant nucleus of significant size. HST observations at the predicted position of this remnant would yield the most sensitive estimate possible for the size of any remaining large object and would provide important new insights into the structure of cometary nuclei and the mechanism by which they fragment. ------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 2] Observations Description ------------------------ This program has been allocated 3 orbits, each of which is a separate visit because different GSs are needed for each orbit owing to the comet's rapid motion (up to ~0.1"/sec). The timeline is as follows: Visit 1: Two WFPC2 F675W images of target #1 = LINEAR Visit 2: Two WFPC2 F675W images of target #2 = LINEAR-OFF1 Visit 3: Two WFPC2 F675W images of target #3 = LINEAR-OFF2 Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: LINEAR ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: Comet LINEAR ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=0.76513729,E=0.999447059,I= | 149.390498,O=83.1909744,W=151.04895406,T | = 26-Jul- | 2000:04:10:37.0,EQUINOX=J2000,EPOCH=04- | Aug-2000 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 15.3+/-1 | JPL-87 orbital elements. B-V = 0.8 | V-R = 0.4 | | Ephemeris Uncertainty: 5800 KM | Acquisition Uncertainty: 10 " | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: LINEAR-OFF1 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: Comet LINEAR-OFF1 ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=0.76513729,E=0.999447059,I= | TYPE=POS_ANGLE,RAD=80,ANG=180,REF=SUN 149.390498,O=83.1909744,W=151.04895406,T | = 26-Jul- | 2000:04:10:37.0,EQUINOX=J2000,EPOCH=04- | Aug-2000 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 15.3+/-1 | Offset by 80 arcsec tailward from B-V = 0.8 | JPL-87 orbital elements. V-R = 0.4 | | Ephemeris Uncertainty: 5800 KM | Acquisition Uncertainty: 10 " | ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 4] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 | TARGET NAME: LINEAR-OFF2 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: Comet LINEAR-OFF1 ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=0.76513729,E=0.999447059,I= | TYPE=POS_ANGLE,RAD=160,ANG=180,REF=SUN 149.390498,O=83.1909744,W=151.04895406,T | = 26-Jul- | 2000:04:10:37.0,EQUINOX=J2000,EPOCH=04- | Aug-2000 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 15.3+/-1 | Offset by 160 arcsec tailward from B-V = 0.8 | JPL-87 orbital elements. V-R = 0.4 | | Ephemeris Uncertainty: 5800 KM | Acquisition Uncertainty: 10 " | ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 5] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 03-AUG-2000 AND 13-AUG-2000 GROUP 1-3 WITHIN 1D SCHED 100% On Hold Comments: Additional Comments: First pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=0.5 1 2200 S REQ EPHEM CORR OFF0 GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 6] Visit: 02 Visit Priority: Visit Requirements: SCHED 100% GUID TOL 0.3" On Hold Comments: Additional Comments: Second pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR-OFF1 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S REQ EPHEM CORR OFF1 GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 2 LINEAR-OFF1 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S NEW ALIGNMENT REQ EPHEM CORR OFF1 Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 7] Visit: 03 Visit Priority: Visit Requirements: SCHED 100% GUID TOL 0.3" On Hold Comments: Additional Comments: Third pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S REQ EPHEM CORR OFF2 GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 2 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S NEW ALIGNMENT REQ EPHEM CORR OFF2 Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 8] Visit: 11 Visit Priority: Visit Requirements: BETWEEN 03-AUG-2000 AND 13-AUG-2000 GROUP 11-13 WITHIN 1D SCHED 100% On Hold Comments: Additional Comments: First pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=0.5 1 2200 S REQ EPHEM CORR OFF0A GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 9] Visit: 12 Visit Priority: Visit Requirements: SCHED 100% GUID TOL 0.3" On Hold Comments: Additional Comments: Second pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR-OFF1 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S REQ EPHEM CORR OFF1A GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 2 LINEAR-OFF1 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S NEW ALIGNMENT REQ EPHEM CORR OFF1A Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 10] Visit: 13 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: Third pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR-OFF2 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=0.5 1 2200 S REQ EPHEM CORR OFF2A GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 11] Visit: 21 Visit Priority: Visit Requirements: BETWEEN 03-AUG-2000 AND 13-AUG-2000 GROUP 21-23 WITHIN 1D SCHED 100% On Hold Comments: Additional Comments: First pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=0.5 1 2200 S REQ EPHEM CORR OFF0B GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 12] Visit: 22 Visit Priority: Visit Requirements: SCHED 100% GUID TOL 0.3" On Hold Comments: Additional Comments: Second pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR-OFF1 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S REQ EPHEM CORR OFF1B GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 2 LINEAR-OFF1 WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S NEW ALIGNMENT REQ EPHEM CORR OFF1B Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 13] Visit: 23 Visit Priority: Visit Requirements: SCHED 100% GUID TOL 0.3" On Hold Comments: Additional Comments: Third pointing Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S REQ EPHEM CORR OFF2B GS ACQ SCENARIO SINGLE Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 2 LINEAR WFPC2 IMAGE PC1-FIX F675W CR-SPLIT=NO 1 1000 S NEW ALIGNMENT REQ EPHEM CORR OFF2B Comments: Expand exposures to fill the orbit ------------------------------------------------------------------------------------------------------------------------------------ 8876( 14) - 08/08/00 08:18 - [ 14] Summary Form for Proposal 8876 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 03-AUG-2000 AND 13-AUG-2000 GROUP 1-3 WITHIN 1D SCHED 100% REQ EPHEM CORR OFF0 GS ACQ SCENARIO SINGLE SCHED 100% GUID TOL 0.3" REQ EPHEM CORR OFF1 GS ACQ SCENARIO SINGLE NEW ALIGNMENT REQ EPHEM CORR OFF1 REQ EPHEM CORR OFF2 GS ACQ SCENARIO SINGLE NEW ALIGNMENT REQ EPHEM CORR OFF2 BETWEEN 03-AUG-2000 AND 13-AUG-2000 GROUP 11-13 WITHIN 1D SCHED 100% REQ EPHEM CORR OFF0A GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF1A GS ACQ SCENARIO SINGLE NEW ALIGNMENT REQ EPHEM CORR OFF1A SCHED 100% REQ EPHEM CORR OFF2A GS ACQ SCENARIO SINGLE BETWEEN 03-AUG-2000 AND 13-AUG-2000 GROUP 21-23 WITHIN 1D SCHED 100% REQ EPHEM CORR OFF0B GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF1B GS ACQ SCENARIO SINGLE NEW ALIGNMENT REQ EPHEM CORR OFF1B REQ EPHEM CORR OFF2B GS ACQ SCENARIO SINGLE NEW ALIGNMENT REQ EPHEM CORR OFF2B ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F675W ------------------------------------------------------------------------------------------------------------------------------------ Target Names LINEAR LINEAR-OFF1 LINEAR-OFF2 ------------------------------------------------------------------------------------------------------------------------------------