! File: 2442C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:06:39:09 coverpage: title_1: COMETARY PARENT MOLECULES sci_cat: SOLAR SYSTEM sci_subcat: COMETS proposal_for: GO targ_of_opp: X pi_title: PROF. pi_fname: PAUL pi_mi: D. pi_lname: FELDMAN pi_inst: JOHNS HOPKINS UNIVERSITY pi_country: USA pi_phone: 410-516-7339 keywords_1: COMETS, SPECTROSCOPY, ULTRAVIOLET hours_pri: 4.90 num_pri: 3 wf_pc: X hrs: X realtime: X time_crit: X funds_amount: 71000 funds_length: 12 funds_date: JUL-91 pi_position: PROFESSOR OF PHYSICS off_fname: CHERYL-LEE off_lname: HOWARD off_title: ASSISTANT DEAN off_inst: JOHNS HOPKINS UNIVERSITY off_addr_1: HOMEWOOD RESEARCH ADMINISTRATION off_addr_2: MERRYMAN HALL off_city: BALTIMORE off_state: MD off_zip: 21218 off_country: USA off_phone: 410-516-8668 ! end of coverpage abstract: line_1: We propose to use HRS observations of a suitable target-of-opportunity comet to line_2: study two outstanding problems related to the composition of the volatile line_3: component of the cometary nucleus. These problems concern two species, CO and line_4: S2, which have been observed in the cometary coma and identified as "parent" line_5: molecules sublimating directly from the nucleus. Both of these molecules have line_6: their principal fluorescent emissions in the vaccuum ultraviolet. The high line_7: spectral resolution will allow the determination of the rotational temperature line_8: of CO, which is diagnostic of the source temperature and the excitation line_9: mechanism of the observed emission. The determination of the abundance of both line_10: CO and S2 in the primarily water ice of the nucleus can serve to constrain line_11: current models of comet formation in the primordial solar nebula. ! ! end of abstract general_form_proposers: lname: A'HEARN fname: MICHAEL title: PROF. mi: F. inst: MARYLAND, UNIVERSITY OF country: USA ! lname: FELDMAN fname: PAUL title: PROF. mi: D. inst: JOHNS HOPKINS UNIVERSITY country: USA ! lname: WEAVER fname: HAROLD title: DR. mi: A. inst: STSCI country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Due to the motion of the comet on the sky, which is typically greater line_2: than 2 arc minutes per hour, it will be necessary to use a different pair of line_3: guide stars for each visit to the comet. During the first visit, a WFC line_4: image will be obtained with real-time contact to verify the calculated line_5: ephemeris position and moving target rate. WFC images will be taken after line_6: each GHRS exposure to determine the actual pointing during data analysis. line_8: All of the science data will be acquired using the Large Science line_9: Aperture (LSA) of the GHRS. The following observations will be made: line_11: (This section was modified 30 September 1991 because of the problem with line_12: side 1 of the GHRS.) line_14: 1) Use G160M in three separate bands to observe the major CO Fourth line_15: Positive Bands to determine both the optical depth in the strong (2,0) line_16: and (1,0) bands and the rotational temperature. The (0,0) band line_17: region also includes CI lambda 1561 for comparison with models of CO line_18: destruction in the coma. For each of four exposures, the center-of- line_19: brightness of the comet is centered in the LSA. The exposure times line_20: are 20 and 25 minutes. line_22: 2) Repeat (1) in each of the three bands but offset the LSA 10,000 km line_23: from the center-of-brightness towards the sun. The exposure times ! question: 3 section: 2 line_1: are 30 and 32 minutes. line_3: 3) Use G270M at two discrete wavelengths to observe the strongest S2 line_4: bands. One of these bands includes the OH(1,0) band to provide a line_5: simultaneous measure of the water production rate. The comet is line_6: centered in the LSA. line_8: 4) Use G270M in one band, offset by 2" parallel to an edge of the LSA, to line_9: determine scalelength of S2. line_11: 5) Repeat (3) after several orbits to search for time variability. ! question: 6 section: 1 line_1: This is a target-of-opportunity program to be activated upon the line_2: apparition of a suitable comet. The observations are time-critical in that line_3: a comet will be optimally placed for observation only for a period of days line_4: or weeks. Real-time contact is necessary to establish the correctness of line_5: the cometary ephemeris, both for position and moving target rate. ! question: 8 section: 1 line_1: The probability of occurence of a suitable target-of-opportunity comet line_2: can be estimated using our collective experience with IUE since the line_3: observing constraints (e.g., solar avoidance angle) are similar to those for line_4: HST. During the past ten years, of the 30 comets observed by IUE, 14 line_5: were target-of-opportunity and 16 were known periodic comets (P/Encke was line_6: observed on 3 separate apparitions; P/Borrelly on 2). Of the 14, 5 line_7: of the target-of-opportunity comets satisfied the criteria given in Section line_8: 5 above, so that the probability of occurence is 50%. It should also be line_9: noted that a long time (12.5 years) has elapsed since the apparition of a line_10: bright "naked-eye" comet (West 1976 VI) and although these occur with a line_11: frequency of one or two per decade, none has appeared since the launch line_12: of IUE. ! !end of general form text general_form_address: lname: FELDMAN fname: PAUL mi: D. category: PI inst: CENTER FOR ASTROPHYSICAL SCIENCES addr_1: JOHNS HOPKINS UNIVERSITY addr_2: DEPT. OF PHYSICS AND ASTRONOMY city: BALTIMORE state: MD zip: 21218 country: USA ! ! end of general_form_address records ! No fixed target records found solar_system_targets: targnum: 1 name_1: COMET-SL-1991A1 descr_1: COMET SHOEMAKER LEVY 1991A1 lev1_1: TYPE = COMET, lev1_2: Q = 0.8367203, E = 0.9998587, lev1_3: O = 49.05506, W = 145.22740, lev1_4: I = 113.50885, lev1_5: T = 24-JUL-92:13:16:48, lev1_6: EQUINOX = J2000, lev1_7: EPOCH = 06-AUG-92, ACQ = 0.25 comment_1: OPTIMUM OBSERVING TIME IS NEAR comment_2: PERIHELION. NOMINAL PERIHELION DATE comment_3: IS 24 JUL 1992 BUT WILL NEED UPDATING comment_4: AFTER THE COMET IS RECOVERED. comment_5: TOTAL COMA VISUAL MAGNITUDE SHOULD comment_6: BE ABOUT 7 DURING THE TIME OF comment_7: OBSERVATIONS BUT THIS IS UNCERTAIN. fluxnum_1: 1 fluxval_1: SURF(V) = 12 +/- 1 fluxnum_2: 2 fluxval_2: SURF-LINE(1510) = 15 +/- 5 E-15 fluxnum_3: 3 fluxval_3: W-LINE(1510) = 1.0 +/- 0.2 fluxnum_4: 4 fluxval_4: SURF-LINE(2900) = 50 +/- 20 E-15 fluxnum_5: 5 fluxval_5: W-LINE(5730) = 1.0 +/- 0.2 fluxnum_10: 10 fluxval_10: SIZE = 1 ! targnum: 3 name_1: COMET-SL-OFFSET descr_1: OFFSET COMET SHOEMAKER LEVY 1991A1 lev1_1: TYPE = COMET, lev1_2: Q = 0.836720, E = 0.9998587, lev1_3: O = 49.05506, W = 145.2274, lev1_4: I = 113.50885, lev1_5: T = 24-JUL-92:13:16:48, lev1_6: EQUINOX = J2000, lev1_7: EPOCH = 06-AUG-92, ACQ = 0.25, lev2_1: TYPE = POS_ANGLE, lev2_2: RAD = 15.3, lev2_3: ANG = 0, lev2_4: REF = SUN comment_1: OPTIMUM OBSERVING TIME IS NEAR comment_2: PERIHELION. NOMINAL PERIHELION DATE comment_3: IS 24 JUL 1992 BUT WILL NEED UPDATING comment_4: AFTER THE COMET IS RECOVERED. comment_5: TOTAL COMA VISUAL MAGNITUDE SHOULD comment_6: BE ABOUT 7 DURING THE TIME OF comment_7: OBSERVATIONS BUT THIS IS UNCERTAIN. comment_8: THIS PTG IS OFFSET ABOUT 10000 KM comment_9: FROM THE NUCLEUS TOWARD THE SUN. fluxnum_1: 1 fluxval_1: SURF(V) = 12 +/- 1 fluxnum_2: 2 fluxval_2: SURF-LINE(1510) = 15 +/- 5 E-15 fluxnum_3: 3 fluxval_3: W-LINE(1510) = 1.0 +/- 0.2 fluxnum_4: 4 fluxval_4: SURF-LINE(2900) = 50 +/- 20 E-15 fluxnum_5: 5 fluxval_5: W-LINE(5730) = 1.0 +/- 0.2 fluxnum_10: 10 fluxval_10: SIZE = 1 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: IMAGE targname: COMET-SL-1991A1 config: WFC opmode: IMAGE aperture: W2 sp_element: F785LP num_exp: 1 time_per_exp: 20 S fluxnum_1: 1 fluxnum_2: 10 priority: 1 param_1: PRE-FLASH=YES param_2: CR-SPLIT=NO req_1: POS TARG -20,+20; comment_1: WFC IMAGE IS USED FOR comment_2: DETERMINING POINTING comment_3: ERROR. TARGET IS TO BE comment_4: PLACED AT ABOUT 20 ARCSEC comment_5: FROM THE PYRAMID APEX. ! linenum: 1.100 sequence_1: DEFINE sequence_2: IMAGE-DUM targname: COMET-SL-1991A1 config: WFC opmode: IMAGE aperture: W2 sp_element: F785LP num_exp: 1 time_per_exp: 0.11 S fluxnum_1: 1 fluxnum_2: 10 priority: 3 param_1: PRE-FLASH=NO param_2: CR-SPLIT=NO req_1: POS TARG -20,+20; comment_1: DUMMY EXP FOR USE WHEN comment_2: TRACKING UNDER GYRO comment_3: CONTROL. EXP TIME IS comment_4: ARBITRARY. ! linenum: 2.000 sequence_1: DEFINE sequence_2: ON-1595 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1595 num_exp: 1 time_per_exp: 20M s_to_n: 10 s_to_n_time: 30M fluxnum_1: 2,3 priority: 1 param_1: FP-SPLIT=STD comment_1: NUCLEUS POINTING. ! linenum: 2.100 sequence_1: DEFINE sequence_2: DUMMY-1595 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1595 num_exp: 1 time_per_exp: 57.6S s_to_n: 10 s_to_n_time: 30M fluxnum_1: 2,3 priority: 3 param_1: FP-SPLIT=STD comment_1: DUMMY EXP FOR USE WHEN comment_2: TRACKING UNDER GYRO comment_3: CONTROL. EXP TIME IS comment_4: ARBITRARY. ! linenum: 3.000 sequence_1: DEFINE sequence_2: OFF-1595 targname: COMET-SL-OFFSET config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1595 num_exp: 1 time_per_exp: 20M s_to_n: 5 s_to_n_time: 40M fluxnum_1: 2,3 priority: 4 param_1: FP-SPLIT=STD comment_1: OFFSET 10000 KM SUNWARD comment_2: FROM THE NUCLEUS. ! linenum: 4.000 sequence_1: DEFINE sequence_2: ON-1475 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1475 num_exp: 1 time_per_exp: 20M s_to_n: 10 s_to_n_time: 30M fluxnum_1: 2,3 priority: 1 param_1: FP-SPLIT=STD comment_1: NUCLEUS POINTING. ! linenum: 4.100 sequence_1: DEFINE sequence_2: DUMMY-1475 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1475 num_exp: 1 time_per_exp: 57.6S s_to_n: 10 s_to_n_time: 30M fluxnum_1: 2,3 priority: 3 param_1: FP-SPLIT=STD comment_1: DUMMY EXP FOR USE WHEN comment_2: TRACKING UNDER GYRO comment_3: CONTROL. EXP TIME IS comment_4: ARBITRARY. ! linenum: 5.000 sequence_1: DEFINE sequence_2: OFF-1475 targname: COMET-SL-OFFSET config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1475 num_exp: 1 time_per_exp: 20M s_to_n: 5 s_to_n_time: 40M fluxnum_1: 2,3 priority: 3 param_1: FP-SPLIT=STD comment_1: OFFSET 10000 KM SUNWARD comment_2: FROM THE NUCLEUS. ! linenum: 6.000 sequence_1: DEFINE sequence_2: ON-1550 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1550 num_exp: 1 time_per_exp: 20M s_to_n: 10 s_to_n_time: 30M fluxnum_1: 2,3 priority: 1 param_1: FP-SPLIT=STD comment_1: NUCLEUS POINTING. ! linenum: 6.100 sequence_1: DEFINE sequence_2: DUMMY-1550 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1550 num_exp: 1 time_per_exp: 57.6S s_to_n: 10 s_to_n_time: 30M fluxnum_1: 2,3 priority: 3 param_1: FP-SPLIT=STD comment_1: DUMMY EXP FOR USE WHEN comment_2: TRACKING UNDER GYRO comment_3: CONTROL. EXP TIME IS comment_4: ARBITRARY. ! linenum: 7.000 sequence_1: DEFINE sequence_2: OFF-1550 targname: COMET-SL-OFFSET config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1550 num_exp: 1 time_per_exp: 20M s_to_n: 5 s_to_n_time: 40M fluxnum_1: 2,3 priority: 4 param_1: FP-SPLIT=STD comment_1: OFFSET 10000 KM SUNWARD comment_2: FROM THE NUCLEUS. ! linenum: 8.000 sequence_1: DEFINE sequence_2: ON-2905 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2905 num_exp: 1 time_per_exp: 20M s_to_n: 10 s_to_n_time: 30M fluxnum_1: 4,5 priority: 1 param_1: FP-SPLIT=STD comment_1: NUCLEUS POINTING. ! linenum: 8.100 sequence_1: DEFINE sequence_2: DUMMY-2905 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2905 num_exp: 1 time_per_exp: 57.6S s_to_n: 10 s_to_n_time: 30M fluxnum_1: 4,5 priority: 3 param_1: FP-SPLIT=STD comment_1: DUMMY EXP FOR USE WHEN comment_2: TRACKING UNDER GYRO comment_3: CONTROL. EXP TIME IS comment_4: ARBITRARY. ! linenum: 9.000 sequence_1: DEFINE sequence_2: OFF-2905 targname: COMET-SL-OFFSET config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2905 num_exp: 1 time_per_exp: 20M s_to_n: 5 s_to_n_time: 40M fluxnum_1: 4,5 priority: 4 param_1: FP-SPLIT=STD comment_1: OFFSET 10000 KM SUNWARD comment_2: FROM THE NUCLEUS. ! linenum: 10.000 sequence_1: DEFINE sequence_2: ON-2844 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2844 num_exp: 1 time_per_exp: 20M s_to_n: 10 s_to_n_time: 30M fluxnum_1: 4,5 priority: 1 param_1: FP-SPLIT=STD comment_1: NUCLEUS POINTING. ! linenum: 11.100 sequence_1: DEFINE sequence_2: DUMMY-2844 targname: COMET-SL-1991A1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2844 num_exp: 1 time_per_exp: 57.6S s_to_n: 10 s_to_n_time: 30M fluxnum_1: 4,5 priority: 3 param_1: FP-SPLIT=STD comment_1: DUMMY EXP FOR USE WHEN comment_2: TRACKING UNDER GYRO comment_3: CONTROL. EXP TIME IS comment_4: ARBITRARY. ! linenum: 12.000 sequence_1: DEFINE sequence_2: OFF-2844 targname: COMET-SL-OFFSET config: HRS opmode: ACCUM aperture: 2.0 sp_element: G270M wavelength: 2844 num_exp: 1 time_per_exp: 20M s_to_n: 5 s_to_n_time: 40M fluxnum_1: 4,5 priority: 4 param_1: FP-SPLIT=STD comment_1: OFFSET 10000 KM SUNWARD comment_2: FROM THE NUCLEUS. ! linenum: 13.000 sequence_1: USE sequence_2: IMAGE-DUM comment_1: USE ONLY IF NEXT WFC comment_2: IMAGE REQUIRES GYRO comment_3: TRACKING. ! linenum: 13.100 sequence_1: USE sequence_2: IMAGE req_1: RT ANALYSIS FOR 14.1,15.1,16.1; req_2: DEC TIME 8.5M; req_3: SEQ 13.1-16.1 WITHIN 1D; req_4: CRIT OBS / 13.0-27.1; req_5: TARG OF OPP / 13.0-27.1; req_6: CYCLE 1 / 13.0-27.1; ! linenum: 14.000 sequence_1: USE sequence_2: DUMMY-1475 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 14.100 sequence_1: USE sequence_2: ON-1475 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 15.000 sequence_1: USE sequence_2: DUMMY-1550 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 15.100 sequence_1: USE sequence_2: ON-1550 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 16.000 sequence_1: USE sequence_2: DUMMY-1595 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 16.100 sequence_1: USE sequence_2: ON-1595 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 17.000 sequence_1: USE sequence_2: IMAGE-DUM comment_1: USE ONLY IF NEXT WFC comment_2: IMAGE REQUIRES GYRO comment_3: TRACKING. ! linenum: 17.100 sequence_1: USE sequence_2: IMAGE req_1: RT ANALYSIS FOR 18.1,19.1,20.1; req_2: DEC TIME 8.5M; req_3: SEQ 17.1-20.1 WITHIN 1D; ! linenum: 18.000 sequence_1: USE sequence_2: DUMMY-1475 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 18.100 sequence_1: USE sequence_2: ON-1475 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 19.000 sequence_1: USE sequence_2: DUMMY-1475 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 19.100 sequence_1: USE sequence_2: OFF-1475 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 20.000 sequence_1: USE sequence_2: DUMMY-1595 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 20.100 sequence_1: USE sequence_2: ON-1595 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 21.000 sequence_1: USE sequence_2: IMAGE-DUM comment_1: USE ONLY IF NEXT WFC comment_2: IMAGE REQUIRES GYRO comment_3: TRACKING. ! linenum: 21.100 sequence_1: USE sequence_2: IMAGE req_1: RT ANALYSIS FOR 22.1,23.1,24.1; req_2: DEC TIME 8.5M; req_3: SEQ 21.1-24.1 WITHIN 1D; ! linenum: 22.000 sequence_1: USE sequence_2: DUMMY-2905 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 22.100 sequence_1: USE sequence_2: ON-2905 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 23.000 sequence_1: USE sequence_2: DUMMY-2844 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 23.100 sequence_1: USE sequence_2: ON-2844 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 24.000 sequence_1: USE sequence_2: DUMMY-1550 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 24.100 sequence_1: USE sequence_2: ON-1550 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 25.000 sequence_1: USE sequence_2: IMAGE-DUM comment_1: USE ONLY IF NEXT WFC comment_2: IMAGE REQUIRES GYRO comment_3: TRACKING. ! linenum: 25.100 sequence_1: USE sequence_2: IMAGE req_1: RT ANALYSIS FOR 26.1,27.1; req_2: DEC TIME 8.5M; req_3: SEQ 25.1-27.1 WITHIN 1D; ! linenum: 26.000 sequence_1: USE sequence_2: DUMMY-2905 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 26.100 sequence_1: USE sequence_2: ON-2905 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! linenum: 27.000 sequence_1: USE sequence_2: DUMMY-2844 comment_1: USE ONLY IF THE comment_2: FOLLOWING GHRS EXP comment_3: REQUIRES GYRO TRACKING. ! linenum: 27.100 sequence_1: USE sequence_2: ON-2844 comment_1: POINTING OFFSET COMMAND MUST comment_2: BE UPLINKED PRIOR TO THIS EXP. ! ! end of exposure logsheet ! No scan data records found