! File: 2446C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:06:44:13 coverpage: title_1: TIME-RESOLVED SPECTROPHOTOMETRY OF ECLIPSING CATACLYSMIC VARIABLES sci_cat: STELLAR ASTROPHYSICS sci_subcat: ERUPTIVE BINARIES proposal_for: GO pi_title: DR. pi_fname: KEITH pi_lname: HORNE pi_inst: STSCI pi_country: USA pi_phone: 301-338-4964 keywords_1: WHITE DWARF, ECLIPSING BINARY, INTERACTING BINARY, keywords_2: DWARF NOVA, ACCRETTION hours_pri: 38.60 num_pri: 8 fos: X time_crit: X funds_amount: 524444 funds_length: 24 funds_date: MAR-90 pi_position: DR. off_fname: H. off_mi: S. off_lname: STOCKMAN off_title: DEPUTY DIRECTOR off_inst: SPACE TELESCOPE SCIENCE INSTITUTE off_addr_1: 3700 SAN MARTIN DRIVE off_city: BALTIMORE off_state: MD off_zip: 21218 off_country: USA off_phone: 301-338-4730 ! end of coverpage abstract: line_1: We will use the Faint Object Spectrograph to acquire time-resolved ultraviolet line_2: spectrophotometry of 8 eclipsing cataclysmic variables covering the full range line_3: of binary periods (1.5 to 8h) and accretion disk morphologies for these line_4: systems. Light-curve synthesis and maximum entropy mapping techniques will be line_5: used to interpret the eclipse data to determine the masses, radii and line_6: temperatures of the component stars, the physical conditions in the accretion line_7: disk and boundary layer between the accretion disk and its central white dwarf, line_8: and the rates of mass transfer. The ultraviolet spectra and ultraviolet line_9: eclipse light curves are crucial because they probe the hot inner regions of line_10: the accretion disk and the boundary layer between the accretion disk and the line_11: white dwarf. The results will test theories of the structure of accretion line_12: disks and theories of the structure and evolution of close binaries in the late line_13: stages of their evolution. ! ! end of abstract general_form_proposers: lname: POLIDAN fname: R. title: DR. mi: S. inst: ARIZONA, UNIVERSITY OF country: USA ! lname: ROBINSON fname: E. title: DR. mi: L. inst: TEXAS, UNIVERSITY OF country: USA ! lname: SHAFTER fname: ALLEN title: DR. mi: W. inst: TEXAS, UNIVERSITY OF country: USA ! lname: SZKODY fname: PAULA title: DR. inst: WASHINGTON, UNIVERSITY OF country: USA ! lname: WADE fname: R. title: DR. mi: A. inst: ARIZONA, UNIVERSITY OF country: USA ! lname: WOOD fname: J. title: DR. mi: H. inst: TEXAS, UNIVERSITY OF country: USA ! lname: ZHANG fname: ER title: DR. mi: H. inst: TEXAS, UNIVERSITY OF country: USA ! lname: PATTERSON fname: J. title: DR. inst: COLUMBIA UNIVERSITY country: USA ! lname: RAYMOND fname: JOHN title: DR. mi: C. inst: CFA country: USA ! lname: HORNE fname: KEITH title: P.I. inst: STSCI country: USA ! lname: MARSH fname: TOM title: DR. inst: STSCI country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: PHASE I PROPOSAL: line_3: We will obtain time-resolved spectrophotometry of the eclipses of selected line_4: cataclysmic variables using the Faint Object Spectrograph. The eclipses last line_5: from roughly 10 min in HT Cas to 1.5 hr in V363 Aur, and during the eclipses line_6: the systems vary on timescales as short as a few seconds. We will use the FOS line_7: in the ``RAPID READOUT'' mode to resolve these variations. Including line_8: observations just before and after the eclipses (needed to establish baselines line_9: and measure out-of-eclipse variations), the individual observations will take line_10: between 58 min and 140 min, depending on the target. We will observe several line_11: eclipses for each system to distinguish systematic eclipse line_12: features from the random ``flickering'' variations characteristic of line_13: cataclysmic variables. In three cases we will observe during out-of-eclipse line_14: phases to determine what ultraviolet variations are associated with the large line_15: large orbital ``hump'' that is seen in the optical. For each system the line_16: observations should be obtained as close together in time as possible in order line_17: to reduce the effect of secular variations on the properties of the eclipses. ! question: 3 section: 2 line_1: We are interested primarily in the continuum and its variations, and in line_2: emission line fluxes rather than line profiles, and will therefore use low line_3: dispersions to obtain broad wavelength coverage. For half the line_4: eclipses we will use the G160L disperser and the blue Digicon, giving spectral line_5: coverage from 1150 to 2500 Angstroms. For the other half we will use the line_6: PRISM disperser and the red Digicon, covering 1850 to 7000 Angstroms. The line_7: longer wavelengths are essential to (1) tie FOS to ground-based observations line_8: and (2) provide maximum sensitivity to optically thin radiation. ! question: 3 section: 3 line_1: Our faintest target (HT Cas) has visual magnitude 16.4 outside of eclipse, and line_2: an energy distribution that is approximately flat in F_nu. We estimate that line_3: using G160L we will detect about 340 photons in 10 seconds in a 100 Angstrom line_4: bandpass centered at 2000 Angstroms, for a signal-to-noise ratio of 20. We line_5: expect flickering variations to be present at about this same level in all line_6: objects. With three eclipses, this should be adequate to separate the white line_7: dwarf from the boundary layer using their contributions to the shape of ingress line_8: and egress, which last about 60 seconds. ! question: 3 section: 4 line_1: We expect that the time-critical nature of the observations and the need for line_2: uninterrupted long exposures (Section 5) will make scheduling difficult. We line_3: therefore request long-term status (two years), to ensure that all the line_4: observations can be made. During the first year we request that 10.5 hours line_5: observing time be allocated for observations of our two top priority targets. line_6: The remaining time should be allocated for the second year. ! question: 3 section: 5 line_1: PHASE II PROPOSAL: line_3: Given a Cycle 1 allocation of 4.0 hours supplemental priority time, line_4: our strategy is to concentrate on eclipses of HT Cas. line_5: HT Cas is in the continuous viewing zone, and it has eclipses line_6: every 106 minutes that will be covered with 25 minutes on-target line_7: exposure time. Thus the time-critical nature of the experiment line_8: should not be too restrictive even given its supplemental priority. line_9: We plan 10 sec time-resolution coverage of 5 eclipses, line_10: 3 eclipses with FOS,BLUE,G160L, and 2 with FOS,RED,PRISM. line_11: The G160L order-zero spectrum records a broad-band optical flux line_12: simultaneously with each first order UV spectra. line_13: A short FOS,BLUE,PRISM exposure is taken just after each blue eclipse. line_14: The 5 eclipses should be scheduled as close together in time line_15: as possible to minimize any long-term secular variations. ! question: 6 section: 1 line_1: We request time-critical observations for two reasons. First, the observations line_2: must cover specific orbital phases, usually phases centered on eclipse but in line_3: other cases phases that include two successive eclipses. Second, we must line_4: observe three (or four) eclipses of each star so we can identify features in line_5: the light curves caused by flickering variations as opposed to eclipses. The line_6: cataclysmic variables vary secularly, and as the time interval between the line_7: eclipses increases, the size of secular changes in the systems will increase. line_8: All observations of a given target should, if possible, be obtained within a line_9: period of one or two weeks to minimize the effect of these secular variations. ! question: 6 section: 2 line_1: The cataclysmic variables vary secularly, so it is difficult to construct line_2: eclipse light curves by joining parts of many different eclipses. Whole line_3: eclipses must be observed whenever possible. To observe whole eclipse light line_4: curves, it is necessary to have uninterrupted long exposures. ! question: 8 section: 1 line_1: The proposed HST observations are self contained: the eclipse analyses will line_2: yield new and significant information even if no other data are available. We line_3: feel strongly, however, that the scientific results of the eclipse analyses line_4: will be greater if the spectrophotometry from HST is complemented by photometry line_5: or spectrophotometry at other wavelengths. We will therefore attempt to obtain line_6: contemporaneous or even simultaneous observations at other wavelengths. We have line_7: access to ground-based telescopes at the McDonald, La Palma, Manastash Ridge, line_8: Mount Hopkins, Kitt Peak and Cerro Tololo observatories, and we will request line_9: observing time on these telescopes for supporting eclipse observations at line_10: visual and near-infrared wavelengths. We also have access to the Voyager line_11: spacecraft and a far UV spectral imaging telescope that will fly as an attached line_12: Shuttle payload (Hitch-hiker) and as a Spartan mission. The Voyagers and at line_13: least the Hitch-hiker should be operating during the proposed observing period. line_14: We will attempt with these instruments to acquire simultaneous far-ultraviolet line_15: photometry for the high priority targets. ! !end of general form text general_form_address: lname: HORNE fname: KEITH title: DR. category: PI inst: SPACE TELESCOPE SCIENCE INSTITUTE addr_1: 3700 SAN MARTIN DRIVE city: BALTIMORE state: MD zip: 21218 country: USA ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: HT-CAS descr_1: STAR; ECLIPSING BINARY; DWARF NOVA descr_2: VARIABLE; INTERACTING BINARY pos_1: RA = 01H 10M 13.1S +/- 0.5", pos_2: DEC = +60D 04' 36.0" +/- 0.5", pos_3: PLATE-ID=01MU equinox: 2000 comment_1: VARIABLE STAR. V MAGNITUDE GIVEN comment_2: CORRESPONDS TO FULL RANGE FROM comment_3: QUIESCENCE TO OUTBURST AWAY FROM comment_4: THE ECLIPSE. UV FLUXES SPECIFIED comment_5: FOR QUIESCENCE ONLY. STAR VANISHES comment_6: DURING ECLIPSE. fluxnum_1: 1 fluxval_1: V = 14.5 +/- 2.0, E(B-V) = 0.0 fluxnum_2: 2 fluxval_2: F(1500) = 5 +/- 3 E-15 fluxnum_3: 3 fluxval_3: F(2500) = 3 +/- 2 E-15 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: HTBECL targname: HT-CAS config: FOS/BL opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 10S priority: 1 param_1: FAINT=3300, BRIGHT=330000 req_1: ONBOARD ACQ FOR 2-3 comment_1: BRIGHT AND FAINT SET VERY WIDE BECAUSE comment_2: FIELD SIMPLE BUT OBJECT IS VARIABLE. comment_3: EXPECT 3300 COUNTS/SECOND IF QUIESCENT comment_4: UP TO MAYBE 50 TIMES MORE IN OUTBURST. comment_5: ALSO FLICKERS BY 30 PERCENT IN 10 SEC. ! linenum: 2.000 sequence_1: DEFINE sequence_2: HTBECL targname: HT-CAS config: FOS/BL opmode: RAPID aperture: 1.0 sp_element: G160L wavelength: 1150-2524 num_exp: 1 time_per_exp: 22M priority: 1 param_1: READ-TIME=10 req_1: SEQ 2-3 NON-INT; req_2: ZERO-PHASE JD2443727.93721 +/- 1S ; req_3: PERIOD 0.0736472039D +/- 0.0000000005D ; req_4: PHASE 0.91 +/- 0.02 comment_1: THE EXPOSURE TIME IS DETERMINED BY comment_2: PHASE COVERAGE, NOT SIGNAL-TO-NOISE. comment_3: CENTER THIS EXPOSURE ON PHASE 0.01. comment_4: BINARY PERIOD IS 106M. ! linenum: 3.000 sequence_1: DEFINE sequence_2: HTBECL targname: HT-CAS config: FOS/BL opmode: RAPID aperture: 1.0 sp_element: PRISM wavelength: 1800-5500 num_exp: 1 time_per_exp: 2M priority: 2 param_1: READ-TIME=10 req_1: PHASE 0.2 +/- 0.1 OF REF 2 comment_1: BLUE PRISM EXPOSURE comment_2: IMMEDIATELY AFTER ECLIPSE. ! linenum: 4.000 sequence_1: DEFINE sequence_2: HTRECL targname: HT-CAS config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 10S priority: 1 param_1: FAINT=3300, BRIGHT=330000 req_1: ONBOARD ACQ FOR 5 comment_1: BRIGHT AND FAINT SET VERY WIDE BECAUSE comment_2: FIELD SIMPLE BUT OBJECT IS VARIABLE. comment_3: EXPECT 5600 COUNTS/SECOND IF QUIESCENT comment_4: UP TO MAYBE 50 TIMES MORE IN OUTBURST. comment_5: ALSO FLICKERS BY 30 PERCENT IN 10 SEC. ! linenum: 5.000 sequence_1: DEFINE sequence_2: HTRECL targname: HT-CAS config: FOS/RD opmode: RAPID aperture: 1.0 sp_element: PRISM wavelength: 1800-8000 num_exp: 1 time_per_exp: 24M priority: 1 param_1: READ-TIME=10 req_1: NON-INT ; req_2: PHASE 0.90 +/- 0.03 OF REF 2 comment_1: THE EXPOSURE TIME IS DETERMINED BY comment_2: PHASE COVERAGE, NOT SIGNAL-TO-NOISE. comment_3: CENTER THIS EXPOSURE ON PHASE 0.01. comment_4: BINARY PERIOD IS 106M. ! linenum: 7.000 sequence_1: USE sequence_2: HTBECL ! linenum: 8.000 sequence_1: USE sequence_2: HTRECL ! linenum: 9.000 sequence_1: USE sequence_2: HTBECL ! linenum: 10.000 sequence_1: USE sequence_2: HTRECL ! linenum: 11.000 sequence_1: USE sequence_2: HTBECL ! ! end of exposure logsheet ! No scan data records found