8276( 25) - 06/09/00 12:02 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8276 Version: 25 Check-in Date: 09-Jun-2000 12:01:16 1.Proposal Title: UV Spectroscopic Investigation of any Bright, Newly Discovered Comet ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 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 Southwest Research Institute N ------------------------------------------------------------------------------------ 5. Abstract We propose aTarget of Opportunity program to investigate any bright comet (V<=6) that is newly discovered during Cycle 8, including comets of any dynamical class. Our main scientific objective is to obtain accurate abundance measurements for all known UV-emitting cometary species (CO from the CO 4PG bands, CO2 from the CO Cameron bands, S2 from the S2 B-X bands, CS2 from CS emissions, and \water\ from OH emissions) and to perform a deep search for any previously undetected species. The 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 species (e.g. S2), and investigate the importance of e-impact on CO for the excitation of the Cameron bands. The latter issue can be definitively resolved during high spectral resolution observations of any comet having V<=5. If an exceptionally bright (V<=2) comet is discovered, we would then request Director's Discretionary time to measure the D/H ratio. This program is a continuation of our efforts in previous cycles to observe as many comets as possible with HST for the purpose of doing abundance intercomparisons on a statistically meaningful sample of objects. ------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 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. THIS PROGRAM HAS BEEN ACTIVATED TO OBSERVE C/1999 S4 (LINEAR) DURING JULY 2000. A major uncertainty in our program is what guiding mode we will use. We would like to use FGS tracking, but the ephemeris uncertainty of the comet, and possibly its rate of motion, may preclude doing that. If we are forced to use GYRO mode tracking, then we will probably switch all MAMA observations from L-mode gratings to M-mode gratings (and keeping the same slit sizes) in order to reduce the probability that a bright star will accidently enter the slit. Visits 1 through 9 assume that the observations will be done under FGS lock. Visits 11 through 19 assume that the observations will be done under GYRO control and are put ON HOLD until a final decision is made. EITHER visits 1 through 9 will be executed OR visits 11 through 19 will be executed, but NOT both. In all cases, 1 visit corresponds to 1 orbit because it is virtually certain that the same GS pair will NOT be available for more than 1 orbit. 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 Visits 11-13 : ACQ CCD image + G140M MAMA exposures + CCD image (confirmation) Visits 14-16 : ACQ CCD image + G230M MAMA exposures + CCD image (confirmation) Visits 17-19 : ACQ CCD image + G230LB exposures + CCD image (confirmation) The exact exposure times for the ACQ and confirmation images must be calculated following the selection of the comet. For the observations performed under GYRO control, STScI personnel will have to add "S/C" exposure lines (including the proper "POS TARG" and "ACQ PCS MODE FINE" special requirements) in EACH of the relevant visits (i.e., 11-19, inclusive) to accomodate the GS ACQ that should be performed just prior to the comet observation. In addition, the "ACQ PCS MODE GYRO" special requirement must be added to each exposure sheet line of each visit. The RPS2 s/w will not allow GOs to input these data. In order to make the RPS2 data as realistic as possible, we have NOT used the GENERIC TARGET LIST. Instead we put a DUMMY set of cometary orbital elements into the SOLAR SYSTEM TARGET LIST, so that RPS2 would put in the appropriate MT overheads. When a comet that meets our selection criteria is discovered, we will update the orbital elements. At the time of program activation, the ephemeris is likely to be off by several arcmins, even up to a degree. About 2 weeks prior to the observations, we anticipate that the ephemeris accuracy will be about 1 arcmin, or somewhat less. About 1 week before the observation, we hope that the ephemeris accuracy will be within 30 arcsec, so that GS selection and bright object checking could reasonably be done at that time. At the time of program execution, we expect to know the ephemeris to a few arcsec accuracy. Thus, the offset pointing command that we uplink prior to starting the observations (i.e., the offset specified by the REQ EPHEM CORR special requirement) should place the comet within the 5 x 5 arcsec field used for the target acquisition. The apparent motion of the comet is expected to be in the range of 0.05 arcsec/sec to 1 arcsec/sec with 0.1 arcsec/sec as most likely. Thus, the comet motion should be about 240 arcsec, or 4 arcmin during the 40 mins that we will be trying to track it. In all likelihood, at least part, and maybe all, of the tracking will have to be done under GYRO control. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 3] Data Distribution Paper Products: YES Media: ELECTRONIC Blocking Factor: 10 Ship To: *Dr. Harold Weaver*Dept. of Physics and Astronomy*Johns Hopkins University*3400 North Charles Street*Baltimore, MD 21218 Ship Via: Email: weaver@pha.jhu.edu ------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 4] 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=0.764972937,E=0.999994684,I | =149.3895845,O=83.1900848,W=151.0681839, | T = 26-Jul- | 2000:03:59:05.0,EQUINOX=J2000,EPOCH=04- | Aug-2000 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 15.3+/-1 | JPL-51 orbital elements. B-V = 0.8 | V-R = 0.4 | | Ephemeris Uncertainty: 5800 KM | Acquisition Uncertainty: 10 " | ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 5] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 05-JUL-2000 AND 11-JUL-2000 SEQ 1-9 WITHIN 3D SEQ 1-3 WITHIN 480M 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF1 SEQ CD P 11-12 NON-INT GS ACQ SCENARIO SINGLE Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 12 LINEAR STIS/F TIME-TA 52X0.2 G140L 1425 BUFFER-TIME=5000 1 30 M REQ EPHEM CORR OFF1 UV-MAM G A Comments: Spectoscopic exposure during 1st MT track command ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 6] 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF2 SEQ CD P 21-22 NON-INT GS ACQ SCENARIO SINGLE Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 22 LINEAR 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 ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 7] 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF3 GS CD P ACQ SCENARIO SINGLE SEQ 31-33 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 32 LINEAR 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 LINEAR 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. ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 8] Visit: 04 Visit Priority: Visit Requirements: SEQ 4-6 WITHIN 480M 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF4 GS CD P ACQ SCENARIO SINGLE SEQ 41-42 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 42 LINEAR 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 ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 9] 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF5 GS CD P ACQ SCENARIO SINGLE SEQ 51-52 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 52 LINEAR 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 ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 10] 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF6 GS CD P ACQ SCENARIO SINGLE SEQ 61-63 NON-INT Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 62 LINEAR 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 LINEAR 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. ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 11] Visit: 07 Visit Priority: Visit Requirements: SEQ 7-9 WITHIN 480M 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF7 SEQ CD P 71-72 NON-INT GS ACQ SCENARIO SINGLE Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 72 LINEAR STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=4 1 30 M REQ EPHEM CORR OFF7 CD Comments: First spectroscopic exposures during first orbit. ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 12] 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF8 SEQ CD P 81-82 NON-INT GS ACQ SCENARIO SINGLE Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 82 LINEAR STIS/C ACCUM 52X0.2 G230LB 2375 CR-SPLIT=4 1 30 M REQ EPHEM CORR OFF8 CD Comments: First spectroscopic exposures during first orbit. ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 13] 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 LINEAR STIS/C ACQ F28X50L MIRROR 1 30 S REQ EPHEM CORR OFF9 SEQ CD P 91-92 NON-INT GS ACQ SCENARIO SINGLE Comments: TA sequence ------------------------------------------------------------------------------------------------------------------------------------ 92 LINEAR STIS/C ACCUM 52X0.2 G430M 3423 CR-SPLIT=4 1 24 M REQ EPHEM CORR OFF9 CD Comments: First spectroscopic exposures during first orbit. ------------------------------------------------------------------------------------------------------------------------------------ 94 LINEAR STIS/C ACCUM F28X50L MIRROR CR-SPLIT=NO ,GAIN=4 1 30 S REQ EPHEM CORR OFF9 MAX CD P DUR 100% END ORBIT Comments: Verification image. ------------------------------------------------------------------------------------------------------------------------------------ 8276( 25) - 06/09/00 12:02 - [ 14] Summary Form for Proposal 8276 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 BETWEEN 05-JUL-2000 AND 11-JUL-2000 SEQ 1-9 WITHIN 3D SEQ 1-3 WITHIN 480M SCHED 100% REQ EPHEM CORR OFF1 SEQ 11-12 NON-INT GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF1 SCHED 100% REQ EPHEM CORR OFF2 SEQ 21-22 NON-INT GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF2 REQ EPHEM CORR OFF3 GS ACQ SCENARIO SINGLE SEQ 31-33 NON-INT REQ EPHEM CORR OFF3 REQ EPHEM CORR OFF3 MAX DUR 100% END ORBIT SEQ 4-6 WITHIN 480M SCHED 100% REQ EPHEM CORR OFF4 GS ACQ SCENARIO SINGLE SEQ 41-42 NON-INT REQ EPHEM CORR OFF4 REQ EPHEM CORR OFF5 GS ACQ SCENARIO SINGLE SEQ 51-52 NON-INT REQ EPHEM CORR OFF5 REQ EPHEM CORR OFF6 GS ACQ SCENARIO SINGLE SEQ 61-63 NON-INT REQ EPHEM CORR OFF6 REQ EPHEM CORR OFF6 MAX DUR 100% END ORBIT SEQ 7-9 WITHIN 480M SCHED 100% REQ EPHEM CORR OFF7 SEQ 71-72 NON-INT GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF7 REQ EPHEM CORR OFF8 SEQ 81-82 NON-INT GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF8 REQ EPHEM CORR OFF9 SEQ 91-92 NON-INT GS ACQ SCENARIO SINGLE REQ EPHEM CORR OFF9 REQ EPHEM CORR OFF9 MAX DUR 100% END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L G230L G230LB G430M ------------------------------------------------------------------------------------------------------------------------------------ Target Names LINEAR ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 2376 2375 3423 ------------------------------------------------------------------------------------------------------------------------------------