! File: 1292C.PROP ! Database: PEPDB ! Date: 16-FEB-1994:10:59:21 coverpage: title_1: SURFACE COMPOSITION OF PLUTO/CHARON sci_cat: SOLAR SYSTEM sci_subcat: MINOR PLANETS proposal_for: GTO/OS pi_fname: JOHN pi_mi: J. pi_lname: CALDWELL pi_inst: YORK UNIVERSITY pi_country: CANADA pi_phone: 416-736-2100 X7721 keywords_1: PLUTO/CHARON, METHANE hours_pri: 1.00 num_pri: 1 time_crit: X pi_position: PROFESSOR ! end of coverpage abstract: line_1: Pluto/Charon will be observed at both orbital elongations with the PC grism, to line_2: search CH4 absorptions features (undoubtedly from condensed CH4) on both. line_3: Previous spectroscopy from the ground has not been able to resolve the pair line_4: spatially, so that previous detections of CH4 features have been attributed to line_5: an average planet, not to the individual members of the pair. A special line_6: orientation will be needed, so that the two spectra do not overlap on the line_7: objective grating field of view, forcing the observations to be made near line_8: geocentric Solar opposition, where constraints on the spacecr aft roll angle due line_9: to power concerns will be minimized. Differences in the spectral line_10: characteristics of the two surfaces should be very easy to detect if they line_11: exist. ! ! end of abstract general_form_proposers: lname: CALDWELL fname: JOHN mi: J. inst: YORK UNIVERSITY country: CANADA ! ! end of general_form_proposers block general_form_text: question: 3 section: 0 line_1: Two observations, separated by about 3 Earth days (i.e., by about 1/2 an line_2: orbital period for Pluto/Charon) will be made, preferably near Pluto line_3: opposition, so that role angle constraints are minimal. Roleangle, zero line_4: rotational phase will be specified when an approximate time for the line_5: observations is established. It is requested that the optimum position in the line_6: PC field be used for the grism observation. ! question: 4 section: 0 line_1: ST is required because the Pluto/Charon pair are so close together that their line_2: spectra cannot be individually recorded from the ground. Since Pluto is about line_3: two magnitudes brighter, its spectrum dominates the pair, and virtually nothing line_4: is known about the spectral nature of the fainter component, Charon. line_5: Ground-based observations can barely resolve the two in broad-band filter line_6: images using speckle techniques. ! question: 5 section: 0 line_1: There is no need for real time observations. Scheduling must put the line_2: observations at opposite orbital elongations, so that two hemispheres are line_3: observed independently. Also, it would seem to be most efficient to schedule line_4: the observations at Pluto opposition, so that the effects of role angle on line_5: power constraints can be minimized. ! question: 6 section: 0 line_1: None ! question: 7 section: 0 line_1: The two spectra (Pluto's and Charon's) will be compared to see if there is a line_2: difference attributable to CH(sub)4 absorption bands throughout the near line_3: infrared. There will be some blurring of the Pluto data because of its finite line_4: diameter. At this time, no grism observations of G stars havebeen requested, line_5: but that might change. ! question: 8 section: 0 line_1: Other investigators will be observing Pluto with different science goals in line_2: mind. It would probably be convenient to schedule all such observations line_3: together. ! question: 10 section: 0 line_1: We have a dedicated SUN computer for data analysis. ! question: 13 section: 1 line_1: Two 30 minute exposures, one at each orbital elogation, will be made of line_2: the Pluto/Charon pair with the PC grism (6000 - 10000 A) to search for CH4 line_3: absorption features on Charon as well as Pluto. There has not been any line_4: previous spatially resolved spectroscopy of this pair. ! !end of general form text general_form_address: lname: CALDWELL fname: JOHN mi: J. title: DR. category: PI inst: YORK UNIVERSITY addr_1: PHYSICS DEPT. city: NORTH YORK state: ON zip: M3J 1P3 country: CANADA ! ! end of general_form_address records ! No fixed target records found solar_system_targets: targnum: 1 name_1: PLUTO-CHARON1 descr_1: PLANET PLUTO lev1_1: STD = PLUTO wind_1: OLG OF CHARON BETWEEN 80 100 comment_1: VISUAL MAGNITUDE IS FOR CHARON comment_2: ONLY. (V=15.4 FOR PLUTO) comment_3: TRK = 0.1 fluxnum_1: 1 fluxval_1: V=17.3 ! targnum: 2 name_1: PLUTO-CHARON2 descr_1: PLANET PLUTO lev1_1: STD = PLUTO wind_1: OLG OF CHARON BETWEEN 260 280 comment_1: TRK = 0.1 fluxnum_1: 1 fluxval_1: V=17.3 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 1.000 targname: PLUTO-CHARON1 config: PC opmode: IMAGE aperture: ANY sp_element: G800L wavelength: 6000-10000 num_exp: 1 time_per_exp: 30M s_to_n: 100 fluxnum_1: 1 priority: 2 req_1: ORIENT 131D +/- 60D / 1,2; req_2: CYCLE 2 / 1,2; GROUP 1,2 WITHIN 4D; req_3: AT 8-MAY-1991:00:00:00 +/- 15D comment_1: OPTIMIZE POSITION OF IMAGE ON ANY PC comment_2: QUADRANT FOR BEST GRISM SPECTRUM. comment_3: SPECIFIED TIME IS PLUTO OPPOSITION, comment_4: WHEN PLUTO IS 17 DEG FROM ANTI-SUN. ! linenum: 2.000 targname: PLUTO-CHARON2 config: PC opmode: IMAGE aperture: ANY sp_element: G800L wavelength: 6000-10000 num_exp: 1 time_per_exp: 30M s_to_n: 100 fluxnum_1: 1 priority: 2 comment_1: OPTIMIZE POSITION OF IMAGE ON ANY CCD comment_2: QUADRANT FOR BEST GRISM SPECTRUM. ! ! end of exposure logsheet ! No scan data records found