! Proposal 6591, submission 4 ! PI: Paul D. Feldman ! Received Thu Apr 25 13:37:54 EDT 1996 ! From: pdf@jhu.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6591,v 6.1 1996/04/25 17:42:25 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Lubenow ! Phone: 410-338-4928 , E-mail: lubenow@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-0512.feldman.prop ! Date generated: Fri Dec 22 16:16:08 EST 1995 ! Proposal_Information ! Section 4 Title: A Campaign to Determine the CO and \cotwo\ Abundances in Cometary Nuclei Proposal_Category: GO Scientific_Category: SOLAR SYSTEM Cycle: 6 Investigators PI_name: Paul D. Feldman PI_Institution: The Johns Hopkins University CoI_Name: Michael F. A'Hearn CoI_Institution: University of Maryland Contact: ! Y or N (designate at most one contact) CoI_Name: Michel C. Festou CoI_Institution: Observatoire Midi-Pyr'e n'e es Contact: ! Y or N (designate at most one contact) CoI_Name: Gian Paolo Tozzi CoI_Institution: Osservatorio Astrofisico di Arcetri Contact: ! Y or N (designate at most one contact) CoI_Name: Harold A. Weaver CoI_Institution: Applied Research Corporation Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We propose a campaign to determine the abundances of CO and \cotwo , relative to H IIo , in a significant sample of comets, both targets of opportunity and periodic comets, over the next three years to address fundamental issues in the composition of cometary nuclei. In particular, we seek to reconcile an analysis based on recent HST\ and archival IUE\ data that suggest that the relative abundance of CO and the overall activity of a comet are correlated. The relative \cotwo\ abundance does not seem to be similarly correlated. To address the focussed objective, we require only 5 orbits per comet to obtain the required spectroscopic information. We anticipate that there may be two or three suitable candidates each year. Questions ! Free format text (please update) Observing_Description: To span a significant range of cometary activity, we desire to observe any comet available to observation with HST\ with a production rate of \qhtwoo\ = 2 * 10^28 \mols\ or greater and within ~1 AU of the sun. Our experience with comets Hartley 2 and Shoemaker-Levy (not to be confused with Shoemaker-Levy 9) discussed above demonstrate that sufficient signal-to-noise is obtainable with one hour of integration time using the G190H grating of FOS to achieve detection of or significant upper limits to the CO and \cotwo\ column abundances in the comae of such comets. One other comet was observed by HST , 24P/Schaumasse, in March 1993 when it was at a heliocentric distance of 1.2 AU. The derived H IIo\ production rate of this comet was 1.5 * 10^28 \mols , and an upper limit of 5 Rayleighs emission in the strongest Cameron bands was obtained with 44 minutes of exposure. This serves as a good constraint for future observations. The PI and co- Is have been involved in the observation of over 50 comets, both targets-of-opportunity and periodic comets (some at more than one apparition), by IUE\ over the past 15 years. IUE\ is subject to similar solar avoidance constraints as HST , and the threshold for detectability (of longer wavelength features such as CS, \cotwop , and OH) with the IUE\ spectrographs was similarly of the order of 1 * 10^28 \mols , so that we may expect 2 or 3 comets suitable for observation each year. Our orbit request is based on two targets, each requiring 5 orbits. We also indicate that a similar number of orbits will be required in each of cycles 7 and 8, but this number is subject to change when the STIS instrument sensitivity is properly taken into account. One of our requested targets is the periodic comet 22P/Kopff, which will reach perihelion of 1.58 AU in early July 1996. The water production rate of this comet near perihelion, determined from IUE\ observations made in 1983, is ~ 5 * 10^28 \mols\ (Feldman and Festou 1992). However, since the brightness of the ultraviolet emissions of interest varies as r^-2Delta^-1, where r and Delta are the heliocentric and geocentric distances, respectively, and the viewing geometry in July 1996 will be ideal with Delta = 0.57 AU, our selection criterion is easily satisfied. For each comet to be observed we require five contiguous orbits to obtain the spectra needed to reliably determine the production rates of CO, \cotwo , and H IIo , with minimal effect of cometary variability, if there is any. The first orbit will be a WFPC2 image with the comet located on the PC chip through a wide band red filter (F675W), in order to update the cometary ephemeris on the spacecraft. The last four orbits will utilize the FOS blue side with the 4.\.''3 aperture to maximize the throughput from an extended source. While the red digicon has roughly twice the sensitivity than the blue digicon in the critical region of the G190H grating, the lower dark background and susceptibility to long-wavelength grating scattered light make the blue side preferable. The second orbit will use the FOS with G270H to obtain the OH brightness needed to determine \qhtwoo . An acquisition image will be taken to verify the pointing and any correction, if necessary, will be made if an uplink to the spacecraft is available. The G270H spectrum will also provide a measure of the dust scattered sunlight and the \cotwop\ emission at 2890 Angstrom . The latter may be useful in tying these observations to the IUE\ comet database, although Feldman Etal\ (1996) demonstrate that the \cotwo\ and \cotwop\ abundances in the field of view are not trivially related. The remaining three orbits will be used to acquire approximately one hour of integration time with G190H, to address our objectives of determining the abundances of CO, \cotwo , and C in the coma. Real_Time_Justification: As noted above, some of the comets to be observed may be targets of opportunity and need to be scheduled on relatively short notice following the discovery. Since the ephemerides of such comets is often not well known (uncertainties of a few arc-seconds are not uncommon), it is necessary to use an interactive acquisition and the ability to uplink the position changes before any of the spectroscopic measurements are made. Comet 22P/Kopff reaches perihelion on 2 July 1996 and remains near minimum geocentric distance for the following three weeks. The observations of this comet must be scheduled during this period. Ground-based monitoring of the activity of any of the comets to be observed will be provided by co-I A'Hearn and his collaborators at Lowell Observatory and at Perth, Australia. Co-I Festou will coordinate our program with European millimeter-wave astronomers at SEST or IRAM. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Solar_System_Targets ! Section 5.2 Target_Number: 1 Target_Name: KOPFF Description: COMET 22P/KOPFF Level_1: TYPE = COMET, ! Satellite of Sun Q = 1.5795617, E = 0.5440739, I = 4.72143, O = 120.91329, W = 162.83487, T = 02-JUL-96:04:47:42.9, EQUINOX = J2000, EPOCH = 16-JUL-96 Ephem_Uncert: 50000KM ! Needed for REQ EPHEM CORR sp req Acq_Uncert: 10" ! Needed for SAVE and USE OFFSET sp reqs Window: RANGE KOPFF EARTH LT 0.6 Flux: V = 7.0 +/- 0.5 ! Include at least V and B-V B-V = 0.65 Comments: Requires ephemeris correction. Target_Number: 2 Target_Name: HYAKUTAKE Description: COMET HYAKUTAKE Level_1: TYPE=COMET, ! Satellite of Sun Q=0.230200536, E=0.999887068, I=124.9229369, O=188.0453468, W=130.1786541, T=01-MAY-96:09:26:55, EPOCH=03-MAY-96, EQUINOX=J2000 Ephem_Uncert: 50000 KM Acq_Uncert: 30" Window: Flux: V = 13 ! Include at least V and B-V B-V = 0.8 V-R = 0.4 Comments: V-mag is for 0.7 arcsec diameter aperture. Elements are from Yeomans ref solution 34 and must be updated prior to final scheduling. ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: BETWEEN 18-JUN-96 AND 28-JUL-96 ! Section 7.1 SEQ 1-3 WITHIN 24H GUID TOL 0.2" On_Hold_Comments: Visit_Comments: Visit should be completed in one orbit. Uplink offset correction to comet ephemeris before Visit 2. RANGE and BETWEEN requirements define same window. Exposure_Number: 11 ! Section 6.5 Target_Name: KOPFF Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 10S Special_Requirements: SAVE OFFSET KOPFF ! Section 7.2 REQ EPHEM CORR KOPFA Comments: Determines ephemeris correction for visits 2-3. Exposure_Number: 12 ! Section 6.5 Target_Name: KOPFF Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 40S Special_Requirements: REQ EPHEM CORR KOPFA Exposure_Number: 13 ! Section 6.5 Target_Name: KOPFF Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 180S Special_Requirements: REQ EPHEM CORR KOPFA Exposure_Number: 14 ! Section 6.5 Target_Name: KOPFF Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F439W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 400S Special_Requirements: REQ EPHEM CORR KOPFA Visits ! Section 6 Visit_Number: 2 Visit_Requirements: BETWEEN 18-JUN-96 AND 28-JUL-96 ! Section 7.1 GUID TOL 0.2" On_Hold_Comments: Visit_Comments: Uplink required for ephemeris offset after visit 1. Use "use offset" for all exposures this visit. Exposure_Number: 21 ! Section 6.5 Target_Name: KOPFF Config: FOS/RD Opmode: ACQ Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 40S Special_Requirements: USE OFFSET KOPFF REQ EPHEM CORR KOPFA Comments: Exposure_Number: 22 ! Section 6.5 Target_Name: KOPFF Config: FOS/RD Opmode: ACCUM Aperture: 4.3 Sp_Element: G270H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 24M Special_Requirements: USE OFFSET KOPFF REQ EPHEM CORR KOPFA EXPAND NO SPLIT END ORBIT ! Section 7.2 Comments: Visits ! Section 6 Visit_Number: 3 Visit_Requirements: BETWEEN 18-JUN-96 AND 28-JUL-96 ! Section 7.1 GUID TOL 0.2" On_Hold_Comments: Visit_Comments: Uplink required for ephemeris offset after visit 1. Use "use offset" for all exposures this visit. Exposure_Number: 31 ! Section 6.5 Target_Name: KOPFF Config: FOS/BL Opmode: ACQ Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 200S Special_Requirements: USE OFFSET KOPFF REQ EPHEM CORR KOPFA Comments: Exposure_Number: 32 ! Section 6.5 Target_Name: KOPFF Config: FOS/BL Opmode: ACCUM Aperture: 4.3 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 24M Special_Requirements: USE OFFSET KOPFF REQ EPHEM CORR KOPFA EXPAND NO SPLIT END ORBIT ! Section 7.2 Comments: Exposure_Number: 33 ! Section 6.5 Target_Name: KOPFF Config: FOS/BL Opmode: ACCUM Aperture: 4.3 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 15M Special_Requirements: USE OFFSET KOPFF REQ EPHEM CORR KOPFA EXPAND NO SPLIT Comments: Exposure_Number: 34 ! Section 6.5 Target_Name: KOPFF Config: FOS/BL Opmode: ACCUM Aperture: 4.3 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 18M Special_Requirements: USE OFFSET KOPFF REQ EPHEM CORR KOPFA EXPAND NO SPLIT END ORBIT ! Section 7.2 Comments: Visits ! Section 6 Visit_Number: 4 Visit_Requirements: BETWEEN 02-JUN-96 AND 09-JUN-96 ! Section 7.1 SEQ 4-6 WITHIN 24H SCHED 100% GUID TOL 0.2" On_Hold_Comments: Visit_Comments: Visit should be completed in one orbit. Uplink offset correction to comet ephemeris before Visit 5. Exposure_Number: 41 ! Section 6.5 Target_Name: HYAKUTAKE Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 1S Special_Requirements: SAVE OFFSET HY2 ! Section 7.2 REQ EPHEM CORR HY1 Comments: Determines ephemeris correction for visits 5-6. Exposure_Number: 42 ! Section 6.5 Target_Name: HYAKUTAKE Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 5S Special_Requirements: REQ EPHEM CORR HY1 Exposure_Number: 43 ! Section 6.5 Target_Name: HYAKUTAKE Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 25S Special_Requirements: REQ EPHEM CORR HY1 Exposure_Number: 44 ! Section 6.5 Target_Name: HYAKUTAKE Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F675W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 100S Special_Requirements: REQ EPHEM CORR HY1 Exposure_Number: 45 ! Section 6.5 Target_Name: HYAKUTAKE Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F439W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 40S Special_Requirements: REQ EPHEM CORR HY1 Exposure_Number: 46 ! Section 6.5 Target_Name: HYAKUTAKE Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F439W Wavelength: Optional_Parameters: CR-SPLIT = NO Number_of_Iterations: 2 Time_Per_Exposure: 200S Special_Requirements: REQ EPHEM CORR HY1 Visits ! Section 6 Visit_Number: 5 Visit_Requirements: BETWEEN 02-JUN-96 AND 09-JUN-96 ! Section 7.1 SCHED 100% GUID TOL 0.2" On_Hold_Comments: Visit_Comments: Uplink required for ephemeris offset after visit 4. Use "use offset" for all exposures this visit. Exposure_Number: 51 ! Section 6.5 Target_Name: HYAKUTAKE Config: FOS/RD Opmode: IMAGE Aperture: 4.3 Sp_Element: G270H Wavelength: Optional_Parameters: Y-SIZE=5 Y-SPACE=128 COMB=YES SUB-STEP=4 Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: USE OFFSET HY2 REQ EPHEM CORR HY1 SEQ 51-52 NON-INT Comments: Exposure_Number: 52 ! Section 6.5 Target_Name: HYAKUTAKE Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G270H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 24M Special_Requirements: EXPAND NO SPLIT END ORBIT ! Section 7.2 USE OFFSET HY2 REQ EPHEM CORR HY1 Comments: Visits ! Section 6 Visit_Number: 6 Visit_Requirements: BETWEEN 02-JUN-96 AND 09-JUN-96 ! Section 7.1 SCHED 100% GUID TOL 0.2" On_Hold_Comments: Visit_Comments: Uplink required for ephemeris offset after visit 4. Use "use offset" for all exposures this visit. Exposure_Number: 61 ! Section 6.5 Target_Name: HYAKUTAKE Config: FOS/BL Opmode: IMAGE Aperture: 4.3 Sp_Element: G270H Wavelength: Optional_Parameters: Y-SIZE=5 Y-SPACE=128 COMB=YES SUB-STEP=4 Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: USE OFFSET HY2 REQ EPHEM CORR HY1 SEQ 61-62 NON-INT Comments: Exposure_Number: 62 ! Section 6.5 Target_Name: HYAKUTAKE Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 24M Special_Requirements: EXPAND NO SPLIT END ORBIT ! Section 7.2 USE OFFSET HY2 REQ EPHEM CORR HY1 Comments: Exposure_Number: 63 ! Section 6.5 Target_Name: HYAKUTAKE Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 15M Special_Requirements: EXPAND NO SPLIT USE OFFSET HY2 REQ EPHEM CORR HY1 Comments: Exposure_Number: 64 ! Section 6.5 Target_Name: HYAKUTAKE Config: FOS/BL Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 18M Special_Requirements: EXPAND NO SPLIT END ORBIT ! Section 7.2 USE OFFSET HY2 REQ EPHEM CORR HY1 Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! 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