! File: 4076C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:07:41:25 coverpage: title_1: DO NEPTUNE AND PLUTO HAVE RINGS? sci_cat: SOLAR SYSTEM proposal_for: GTO/HSP cont_id: 1086 pi_fname: ROBERT pi_mi: C. pi_lname: BLESS pi_inst: WISCONSIN, UNIVERSITY OF pi_country: USA pi_phone: 608-262-1715 keywords_1: NEPTUNE, PLUTO, PLANETARY RINGS, OCCULTATIONS, RING keywords_2: IMAGING hours_pri: 4.58 num_pri: 2 realtime: Y time_crit: Y ! end of coverpage abstract: line_1: The origin of planetary ring systems remains line_2: unknown. One common property of the known ringed line_3: planets--Jupiter, Saturn, and Uranus--is that each line_4: possesses a regular satellite system, which would line_5: point to a close connection between the formation of line_6: rings and satellites. However, the dynamical line_7: lifetimes of several important features in Saturn's line_8: are short, which would lead to the conclusion that line_9: these rings are young. Continuing this line of line_10: reasoning, one would conclude that rings are not line_11: formed concurrently with planets--perhaps the line_12: formation of rings depends on encounters of planets line_13: with small bodies, or other random events: ring line_14: systems come and go. The discovery of ring systems line_15: around Neptune and/or Pluto would shift opinion line_16: toward this latter view, while the lack of line_17: detectable rings would greatly strengthen their line_18: apparent connection with regular satellite systems. line_19: The August, 1989 Voyager encounter with Neptune line_20: discovered complete rings with shepherd satellites, ! ! end of abstract general_form_proposers: lname: ROBINSON fname: EDWARD mi: L. inst: TEXAS, UNIVERSITY OF country: USA ! lname: BLESS fname: ROBERT mi: C. inst: WISCONSIN, UNIVERSITY OF country: USA ! lname: VAN CITTERS fname: G. mi: W. inst: NATIONAL SCIENCE FOUNDATION country: USA ! lname: DOLAN fname: JOSEPH mi: F. inst: NASA, GODDARD SPACE FLIGHT CENTER country: USA ! lname: WHITE fname: RICHARD mi: L. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: ELLIOT fname: JAMES mi: L. inst: MASSACHUSETTS INSTITUTE OF TECHNOLOGY country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Our ring search, for both Neptune and Pluto, will line_2: consist of occultations of opportunity, chosen to line_3: probe the equatorial plane of the planet (where line_4: rings are most likely to be). We plan to identify line_5: those occultations of sufficient signal-to-noise line_6: ratio to achieve the goals outlined in Section 2. line_7: Each observation will require (i) an onboard line_8: acquisition, (ii) a scan of about 10 to 20 line_9: arcseconds along the track that the object will line_10: follow relative to the occulting body, and (iii) a line_11: time series run on the object with whatever filter- line_12: aperture combination that is chosen for the line_13: observation. For some occultations to be observed line_14: in the far UV, prior multi-filter photometry of the line_15: object will be necessary in order to determine the line_16: most appropriate filter to use for the occultation. line_17: The default filter set is F750W/F320N. For now, we line_18: shall assume that the calibration and observation line_19: time will require 40 minutes for Pluto and 50 line_20: minutes for Neptune. Cycle 1: all predicted ! question: 4 section: 1 line_1: For occultations, we can achieve a much better line_2: signal-to-noise ratio than would be possible from line_3: the ground for the following reasons: (i) the line_4: greatly improved photometric stability of ST line_5: photometry; (ii) our ability to reject background line_6: light from the occulting object by employing small line_7: focal plane apertures; and (iii) the absence of line_8: scintillation noise, which has strong components at line_9: frequencies comparable to the occultation line_10: timescale. ! question: 6 section: 1 line_1: A prior scan over 10 - 20 arc-seconds is needed to line_2: map the scattered light field, which is needed for line_3: the data reduction. ! question: 7 section: 1 line_1: Data will be reduced and analyzed at MIT with the line_2: DEC5000 belonging to the planetary astronomy group. ! question: 10 section: 1 line_1: Data reduction and analysis will be supported on line_2: computer facilities at MIT. ! question: 13 section: 1 line_1: Ring systems around Pluto will be searched for and line_2: the ring system around Neptune will be probed by line_3: stellar occultation observations with the HSP. The line_4: presence or absence of ring systems around these line_5: planets will be indicative of whether regular line_6: satellite systems are necessary for the formation of line_7: planetary rings. ! !end of general form text general_form_address: lname: BLESS fname: ROBERT mi: C. category: PI inst: UNIVERSITY OF WISCONSIN addr_1: DEPARTMENT OF ASTRONOMY city: MADISON state: WI zip: 53706 country: USA phone: 608-262-1715 ! lname: ELLIOT fname: JAMES mi: L. category: CON inst: MASSACHUSETTS INSTITUTE OF TECHNOLOGY addr_1: BLDG. 54-422 city: CAMBRIDGE state: MA zip: 02139 country: USA phone: 617-253-6308 telex: 921473 MIT CAM ! ! end of general_form_address records fixed_targets: targnum: 11 name_1: N61 descr_1: STAR TO BE OCCULTED BY NEPTUNE. descr_2: CLOSE APPROACH AT 11-JUL-92:18:21:38 pos_1: RA = 19H 15M 58.095S +/- 0.05", pos_2: DEC = -21D 32' 12.92" +/- 0.05", equinox: J2000 acqpr_1: BKG comment_1: SOLAR ELONG 178D fluxnum_1: 1 fluxval_1: V = 14.4 +/- 0.5 ! targnum: 12 name_1: N61-OFFSET name_2: GSC6308-01146 descr_1: OFFSET TARGET FOR N61 pos_1: PLATE-ID = 068E, pos_2: RA = 19H 15M 53.921S +/- 0.05", pos_3: DEC = -21D 32' 18.46" +/- 0.05", equinox: J2000 fluxnum_1: 1 fluxval_1: B = 13.33 +/- 0.48 ! ! end of fixed targets solar_system_targets: targnum: 18 name_1: N61-BACKGROUND descr_1: OFFSET NEPTUNE lev1_1: STD = NEPTUNE lev2_1: TYPE = POS_ANGLE, lev2_2: RAD = 22.2, lev2_3: ANG = 85.0, lev2_4: REF = NORTH comment_1: FOR USE IN A SCAN OF comment_2: BACKGROUND LEVELS ALONG comment_3: THE PATH OF THE OCCULTED STAR ! targnum: 19 name_1: NEPTUNE-CENTER descr_1: PLANET NEPTUNE lev1_1: STD = NEPTUNE, ACQ = 0.1 comment_1: ACQUISITION TARGET FOR comment_2: BACKGROUND SCANS fluxnum_1: 1 fluxval_1: V = 7.8 +/- 0.5 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 4.000 sequence_1: DEFINE sequence_2: ONBRD-ACQ targname: # config: HSP/VIS opmode: ACQ num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 ! linenum: 6.000 sequence_1: DEFINE sequence_2: BACK-SCAN targname: # config: HSP/PMT/VIS opmode: SPLIT aperture: 1.0 sp_element: F750W/F320N num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: # req_1: SPATIAL SCAN; ! linenum: 7.000 sequence_1: DEFINE sequence_2: RING-OCC targname: # config: HSP/PMT/VIS opmode: SPLIT aperture: 1.0 sp_element: F750W/F320N num_exp: 1 time_per_exp: 1M fluxnum_1: 1 priority: 1 param_1: # req_1: CRIT OBS; ! linenum: 10.000 sequence_1: USE sequence_2: ONBRD-ACQ targname: NEPTUNE-CENTER time_per_exp: X4 req_1: ONBOARD ACQ FOR 10.01; req_2: SEQ 10.00 - 10.01 NO GAP; req_3: PCS MODE F / 10.00 - 10.28; ! linenum: 10.010 sequence_1: USE sequence_2: BACK-SCAN targname: N61-BACKGROUND time_per_exp: X91 param_1: SAMPLE-TIME = 0.05, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, req_1: SEQ 10.01 - 10.03; req_2: GROUP 10.01 - 10.04 WITHIN 9H; req_3: CYCLE 2/10.00 - 10.28; ! linenum: 10.020 sequence_1: USE sequence_2: BACK-SCAN targname: N61-BACKGROUND time_per_exp: X91 param_1: SAMPLE-TIME = 0.05, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, ! linenum: 10.030 sequence_1: USE sequence_2: BACK-SCAN targname: N61-BACKGROUND time_per_exp: X91 param_1: SAMPLE-TIME = 0.05, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, ! linenum: 10.040 sequence_1: USE sequence_2: ONBRD-ACQ targname: N61-OFFSET time_per_exp: X40 req_1: ONBOARD ACQ FOR 10.10 - 10.28; req_2: SEQ 10.04 - 10.10 NO GAP; ! linenum: 10.100 sequence_1: USE sequence_2: RING-OCC targname: N61 time_per_exp: X50 param_1: SAMPLE-TIME = 0.1, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, req_1: AT 11-JUL-92:03:31 +/- 1M; comment_1: END EXPOSURE AT 11-JUL-92:04:50. ! linenum: 10.250 sequence_1: USE sequence_2: ONBRD-ACQ targname: NEPTUNE-CENTER time_per_exp: X4 req_1: ONBOARD ACQ FOR 10.26; req_2: SEQ 10.25 - 10.26 NO GAP; ! linenum: 10.260 sequence_1: USE sequence_2: BACK-SCAN targname: N61-BACKGROUND time_per_exp: X91 param_1: SAMPLE-TIME = 0.05, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, req_1: SEQ 10.26 - 10.28; req_2: GROUP 10.10 - 10.28 WITHIN 9H; ! linenum: 10.270 sequence_1: USE sequence_2: BACK-SCAN targname: N61-BACKGROUND time_per_exp: X91 param_1: SAMPLE-TIME = 0.05, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, ! linenum: 10.280 sequence_1: USE sequence_2: BACK-SCAN targname: N61-BACKGROUND time_per_exp: X91 param_1: SAMPLE-TIME = 0.05, param_2: PRECISION = HIGH, param_3: DATA-FORMAT = ALL, param_4: PMT-ANALOG = 1000, param_5: VIS-ANALOG = 100, ! ! end of exposure logsheet scan_data: line_list: 10.01, 10.03, 10.26, 10.28 fgs_scan: cont_dwell: C dwell_pnts: 0 dwell_secs: 0.00 scan_width: 0.0000 scan_length: 29.3000 sides_angle: 90.0000 number_lines: 1 scan_rate: 0.0750 first_line_pa: 262.2000 scan_frame: CEL len_offset: 0. wid_offset: 0. ! line_list: 10.02, 10.27 fgs_scan: cont_dwell: C dwell_pnts: 0 dwell_secs: 0.00 scan_width: 2.0000 scan_length: 29.3000 sides_angle: 90.0000 number_lines: 3 scan_rate: 0.0750 first_line_pa: 262.2000 scan_frame: CEL len_offset: 0. wid_offset: 0.5 ! ! end of scan data