9496( 5) - 04/05/02 15:01 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9496 Version: 5 Check-in Date: 05-Apr-2002 15:00:22 1.Proposal Title: UV Spectroscopic Investigation of any Bright, Newly Discovered Comet ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Harold Weaver The Johns Hopkins University 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-Pyr'e n'e es N CoI: Dr. Gian Paolo Tozzi Osservatorio Astrofisico di Arcetri N ------------------------------------------------------------------------------------ 5. Abstract We propose a Target of Opportunity program to investigate any bright comet (mboxV<=sssim7) that is newly discovered during Cycle 11, including comets of any dynamical class. Our main scientific objective is to obtain accurate abundance measurements for several key cometary species: CO from the CO 4PG bands, \cotwo\ from the CO Cameron bands, \stwo\ from the \stwo\ B-X bands, \cstwo\ from CS emissions, and \water\ from OH emissions. The UV Cameron band emission is currently the only way to probe \cotwo\ in comets. The high sensitivity and long-slit capability of STIS will allow us to characterize the spatial distribution of the coma species, so that we can identify those derived from an extended source (e.g. CO), study the decay of short-lived molecules (e.g. \stwo\ and \cstwo), compare the dust and gas spatial distributions, and investigate the importance of e-impact on CO for the excitation of the Cameron bands (the latter for any comet having mboxV<=sssim5). If an exceptionally bright (V<=sssim2) comet is discovered, we would then request Director's Discretionary time to measure the D/H ratio. This program is a continuation of our successful efforts in previous cycles to observe as many comets as possible with HST, so that we can eventually make abundance intercomparisons on a statistically meaningful sample. Our ambitious scientific objectives are only possible on bright comets, and given the paucity of data on several of the species listed above, these opportunities should not be missed. ------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 2] Observations Description ------------------------ This is a Target of Opportunity program to observe any newly-discovered comet that achieves a water production rate of about 2E29 at 1 AU. This roughly maps into a total visual magnitude limit of about 6. The timeline for the observations are as follows (the lines give the activities that will be executed in EACH orbit). Visits 1-3 : ACQ CCD image + G140L MAMA exposures with 0.2" slit Visits 4-6 : ACQ CCD image + G230L MAMA exposures with 0.5" slit Visits 7-8 : ACQ CCD image + G230LB exposures + CCD image (confirmation) with 0.2" slit Visit 9 : ACQ CCD image + G430M exposures + CCD image (confirmation) with 0.2" slit The exact exposure times for the ACQ and confirmation images must be calculated following the final selection of the comet. ***The following text was added on 2002 March 18*** This program has been activated to observe C/2002 C1 (Ikeya-Zhang), which achieved naked-eye visibility in March 2002. C/I -Z emerges from the solar exclusion zone for HST on 2002 April 14th. We would like to observe as soon after that as possible because the intensities of the primary spectral lines will scale roughly as r^-4, or even r^-6, where "r" is the heliocentric distance. On April 14th, r=0.79 AU and the value monotonically increases from that point on. Typically for cometary programs, GS selection drives the scheduling. In the interest of giving the planners maximum scheduling flexibility, we have tried to minimize the number of special requirements. However, we would still like you to attempt to adhere to the following guidelines to the best of your ability: 1) Schedule the observations as soon as possible after April 14th. 2) Try to schedule all 9 orbits within the smallest amount of clock time. 3) If consecutive orbits are not possible, please keep visits 1-3 as close together as possible. 4) Single GS tracking is fine for our program. 5) Ephemeris offset commands are required every visit (i.e., every orbit) to remove ephemeris error. We ask that you delay final selection of GSs and final scheduling until about 2-3 weeks prior to execution, so that the latest orbital elements can be used. The current elements (i.e., those provided on 3/18/02) probably have a 3-sigma accuracy of ~20 arcsec, which should be sufficient to perform the Bright Object check. Real Time Justification ----------------------- An approximate suitability criterion for the emphTarget of Opportunity observed under this program is that the comet should have: \ Q_H_2O >= 2 * 10^29 * r^2 Delta \ where r and Delta are the heliocentric and geocentric distances, in AU, respectively. This criterion corresponds emphroughly to a comet having a total (integrated over the entire coma) visual magnitude V<=sssim 6-7. Based on IUE and HST experience during the past two decades, a comet satisfying the above criterion should appear about once every 1-2 years. Our observations are time- critical in that the comet will be optimally placed for a period of days to weeks. Typically the comet will be discovered several months prior to the optimal observation time, and the ephemeris uncertainty is usually reduced to an acceptable level for detailed HST planning a few weeks before the observations. We note that comet Hyakutake was only moderately active in terms of its gas production rates (i.e. mbox\qwater<=sssim 2 * 10^29 mol s^-1 for r=1 AU) and was unusual only with respect to its geocentric distance. Comets having line brightnesses within a factor of two of Hyakutake's will not be that unusual. If our program is approved and a suitable target is discovered, then we will attempt to make coordinated ground-based observations having objectives complementary to those of our HST program. However, our ground-based plans will not affect the scheduling of the HST observations, as we will simply make the ground-based observations fit the HST schedule rather than the other way around. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: IKEYA-ZHANG ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: Comet Ikeya-Zhang ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=0.5070604199305608,E=0.9900 | 546786086877,I=28.12168869580074,O=93.36 | 711219789274,W=34.67254903472506,T = 18- | Mar- | 2002:23:32:32.0,EQUINOX=J2000,EPOCH=27- | Mar-2002 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 17+/-2 | JPL-17 orbital elements, including B-V = 0.8 | observations through 2002 Mar 24.8. V-R = 0.4 | | Ephemeris Uncertainty: 3625 KM | Acquisition Uncertainty: 10 " | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: IKEYA-ZHANG-2 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: Comet Ikeya-Zhang ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=0.5070604199305608,E=0.9900 | 546786086877,I=28.12168869580074,O=93.36 | 711219789274,W=34.67254903472506,T = 18- | Mar- | 2002:23:32:32.0,EQUINOX=J2000,EPOCH=27- | Mar-2002 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 17+/-2 | JPL-17 orbital elements, including B-V = 0.8 | observations through 2002 Mar 24.8. V-R = 0.4 | | Ephemeris Uncertainty: 3625 KM | Acquisition Uncertainty: 10 " | ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 4] Visit: 01 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: First of G140L group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF1 SEQ CD P 11-12 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 12 IKEYA-ZHANG STIS/F TIME-TA 52X0.2 G140L 1425 BUFFER-TIME=5000 1 30 M REQ EPHEM CORR OFF1 UV-MAM G A Comments: Spectroscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 5] Visit: 02 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: Second of G140L group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF2 SEQ CD P 21-22 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 22 IKEYA-ZHANG STIS/F TIME-TA 52X0.2 G140L 1425 BUFFER-TIME=5000 1 30 M REQ EPHEM CORR OFF2 UV-MAM G A Comments: Spectoscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 6] Visit: 03 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: Third of G140L group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 31 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF3 SEQ CD P 31-33 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 32 IKEYA-ZHANG STIS/F TIME-TA 52X0.2 G140L 1425 BUFFER-TIME=5000 1 24 M REQ EPHEM CORR OFF3 UV-MAM G A Comments: Spectoscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 33 IKEYA-ZHANG STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO ,GAIN=4 1 30 S REQ EPHEM CORR OFF3 MAX CD P DUR 100% END ORBIT Comments: Verification image. ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 7] Visit: 04 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: First of G230L group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 41 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF4 SEQ CD P 41-42 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 42 IKEYA-ZHANG STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=5000 1 30 M REQ EPHEM CORR OFF4 UV-MAM G A Comments: Spectoscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 8] Visit: 05 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: Second of G230L group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 51 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF5 SEQ CD P 51-52 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 52 IKEYA-ZHANG STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=5000 1 30 M REQ EPHEM CORR OFF5 UV-MAM G A Comments: Spectoscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 9] Visit: 06 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: Third of G230L group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 61 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF6 SEQ CD P 61-63 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 62 IKEYA-ZHANG STIS/N TIME-TA 52X0.5 G230L 2376 BUFFER-TIME=5000 1 24 M REQ EPHEM CORR OFF6 UV-MAM G A Comments: Spectoscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 63 IKEYA-ZHANG STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO ,GAIN=4 1 30 S REQ EPHEM CORR OFF6 MAX CD P DUR 100% END ORBIT Comments: Verification image. ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 10] Visit: 07 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: First of G230LB group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 71 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF7 SEQ -2 CD P 71-72 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 72 IKEYA-ZHANG STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=4 1 30 M REQ EPHEM CORR OFF7 -2 CD Comments: First spectroscopic exposures during first orbit. ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 11] Visit: 08 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: Second of G230LB group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 81 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF8 SEQ -2 CD P 81-82 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 82 IKEYA-ZHANG STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=4 1 30 M REQ EPHEM CORR OFF8 -2 CD Comments: First spectroscopic exposures during first orbit. ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 12] Visit: 09 Visit Priority: Visit Requirements: SCHED 100% On Hold Comments: Additional Comments: First of G430M group Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 91 IKEYA-ZHANG STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF9 SEQ -2 CD P 91-92 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 92 IKEYA-ZHANG STIS/C ACCUM 52X0.2 G430M 3423 CR-SPLIT=4 1 24 M REQ EPHEM CORR OFF9 -2 CD Comments: First spectroscopic exposures during first orbit. ------------------------------------------------------------------------------------------------------------------------------------ 94 IKEYA-ZHANG STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO ,GAIN=4 1 30 S REQ EPHEM CORR OFF9 MAX -2 CD P DUR 100% END ORBIT Comments: Verification image. ------------------------------------------------------------------------------------------------------------------------------------ 9496( 5) - 04/05/02 15:01 - [ 13] Summary Form for Proposal 9496 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2 52X0.5 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ TIME-TAG ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=5000 GAIN=4 CR-SPLIT=NO CR-SPLIT=4 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 100% REQ EPHEM CORR OFF1 SEQ 11-12 NON-INT REQ EPHEM CORR OFF1 REQ EPHEM CORR OFF2 SEQ 21-22 NON-INT REQ EPHEM CORR OFF2 REQ EPHEM CORR OFF3 SEQ 31-33 NON-INT REQ EPHEM CORR OFF3 REQ EPHEM CORR OFF3 MAX DUR 100% END ORBIT REQ EPHEM CORR OFF4 SEQ 41-42 NON-INT REQ EPHEM CORR OFF4 REQ EPHEM CORR OFF5 SEQ 51-52 NON-INT REQ EPHEM CORR OFF5 REQ EPHEM CORR OFF6 SEQ 61-63 NON-INT REQ EPHEM CORR OFF6 REQ EPHEM CORR OFF6 MAX DUR 100% END ORBIT REQ EPHEM CORR OFF7 SEQ 71-72 NON-INT REQ EPHEM CORR OFF7 REQ EPHEM CORR OFF8 SEQ 81-82 NON-INT REQ EPHEM CORR OFF8 REQ EPHEM CORR OFF9 SEQ 91-92 NON-INT REQ EPHEM CORR OFF9 REQ EPHEM CORR OFF9 MAX DUR 100% END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L G230L G230LB G430M ------------------------------------------------------------------------------------------------------------------------------------ Target Names IKEYA-ZHANG IKEYA-ZHANG-2 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 2376 2375 3423 ------------------------------------------------------------------------------------------------------------------------------------