! File: 3824C.PROP ! Database: PEPDB ! Date: 19-FEB-1994:20:45:45 coverpage: title_1: A SEARCH FOR SILICON AND CARBON IN GP COM sci_cat: STELLAR ASTROPHYSICS sci_subcat: PECULIAR BINARIES proposal_for: GO pi_title: DR. pi_fname: JANET pi_mi: H pi_lname: WOOD pi_inst: UNIVERSITY OF TEXAS pi_country: USA pi_phone: 512-471-3432 hours_pri: 3.67 num_pri: 1 fos: Y funds_amount: 76039 funds_length: 12 funds_date: OCT-92 pi_position: HUBBLE FELLOW off_fname: STEPHEN off_mi: A off_lname: MONTI off_title: VICE PROVOST off_inst: UNIVERSITY OF TEXAS off_addr_1: EXECUTIVE VP & PROVOST, 201 MAIN off_city: AUSTIN off_state: TX off_zip: 78712 off_country: USA off_phone: 512-471-4363 ! end of coverpage abstract: line_1: The spectra of the 46 minute period binary white dwarf line_2: GP Com show emission lines line_3: from an accretion disk supplied from the hydrogen-exhausted core of a line_4: star, providing us with an opportunity to see the products of line_5: nucleosynthesis directly. The optical and ultraviolet data taken to date line_6: show evidence for CNO processing, but the abundances of elements such as line_7: silicon, calcium and iron appear anomalously low. The only plausible line_8: explanation for this involves the transfer of nitrogen-rich material line_9: from the progenitor of the accreting white dwarf to its companion line_10: in a common envelope stage. line_12: Confirmation of the low abundance of the heavier elements is a critical line_13: test of this model. We will take high signal-to-noise ultraviolet line_14: spectra of GP Com to search for emission from the SiIV 1400 doublet, line_15: CIV 1550 and other Si and C ions. We will measure the emission from line_16: NV 1239, 1243. This will allow us to determine the extent of CNO line_17: equilibrium and enhancement of nitrogen. These data will constrain line_18: both the evolution of GP Com and the poorly understood common envelope line_19: phase of binary evolution. ! ! end of abstract general_form_proposers: lname: WOOD fname: JANET title: DR. mi: H inst: UNIVERSITY OF TEXAS country: USA esa: N ! lname: MARSH fname: THOMAS title: DR. mi: R inst: UNIVERSITY OF OXFORD country: UK esa: Y ! lname: LAMBERT fname: DAVID title: PROF. mi: L inst: UNIVERSITY OF TEXAS country: USA esa: N ! lname: HORNE fname: KEITH title: DR. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA esa: N ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: ! question: 3 section: 1 line_1: We will take FOS spectra of GP Com through the 4.3arcsec aperture line_2: with the G130H grating. We will observe the range line_3: 1150-1608A in order to cover the SiIV 1394, 1403, CIV 1548, 1551 line_4: and NV 1239, 1243 doublets with the highest sensitivity. We will also cover line_5: CIII 1175, the SiIII complex at 1300, NIV 1486 and several other lines e.g. CII line_6: and SiII. Observation of NV will allow us to compare the strength of the line line_7: with those of Si and C and also allow us to determine whether the accretion line_8: disc contributes to the ultraviolet lines through its characteristic double line_9: peaked profile. This has not been clearly determined for any cataclysmic line_10: variable. The exposures will cover more than two orbits line_11: of GP Com and by reading out the detector every 2 minutes we will obtain line_12: information on orbital variations in the NV line and continuum. line_14: Although GP Com is classed as a cataclysmic variable star, optical observations line_15: have shown little variability in the lines, and thus our observations are not line_16: time critical. ! question: 4 section: 1 line_1: The nitrogen abundance in GP Com has clearly been enhanced by CNO processing. line_2: Our aim is to determine whether another mechanism (e.g. mass transfer from the line_3: star now accreting) has enhanced it still further. Observationally we aim to line_4: detect silicon to pin down the heavy element abundance. Optical data are line_5: already limited by the presence of many weak blended lines (possibly of neon) line_6: which makes reliable estimation of the continuum impossible. Higher spectral line_7: resolution will not resolve these lines since they are intrinsically broad line_8: because of Doppler shifting in the accretion disk. line_10: By analogy with normal CVs, in which silicon is easily detected in the line_11: ultraviolet, it is the best region to look in GP Com. We also gain sensitivity line_12: to a different ion species, SiIV in addition to SiII which will greatly decrease line_13: the uncertainties of the model of the disk's atmosphere. The IUE spectrum of line_14: figure 1 represents a 15,000 sec exposure which has a signal-to-noise roughly a line_15: factor of 5 - 10, too low for our requirements (see the exposure time line_16: computation in the next section). Thus, even if there was no fixed pattern line_17: noise to worry about, our experiment would require a prohibitively long IUE line_18: exposure. HST is the only instrument available that can solve this problem. ! question: 5 section: 1 line_1: ! question: 6 section: 1 line_1: ! question: 7 section: 1 line_1: The data will be processed through the standard software at HST. The subsequent line_2: analysis involves measuring the fluxes of SiIV, CIV, NV and any other lines line_3: that are detected, and then translating these to abundances. We will then be line_4: able to estimate the amount of accreted material necessary to have enhanced the line_5: nitrogen (if the optical results are confirmed). line_7: The observed line strengths will be compared to those in IUE observations of line_8: cataclysmic variables where abundances are approximately solar. Since we will line_9: observe at least two ionic states of C, Si and N we will be able to determine line_10: the temperature of the region producing the lines, and the abundance of each line_11: element. line_13: Further analysis will center on the NV line profile. The spectral resolution line_14: will be sufficient to show the double-peaked profile from the disk, and thus line_15: by implication whether the disk contributes significantly to the ultraviolet line_16: lines. The long exposure time needed means that we will have covered more than line_17: two orbits of GP Com and the NV line and continuum will be investigated for line_18: orbital variations. ! question: 8 section: 1 line_1: ! question: 9 section: 1 line_1: Program GTO-1064 "Boron in Main Sequence Stars": Lambert. line_2: Lambert has received and analysed this data. line_3: Program GO-2380 "Instabilities in Accretion Disks and the Outbursts of Dwarf line_4: Novae": Horne and Marsh. line_5: Data under analysis. line_6: Program GO-2334 "Ultraviolet Spectroscopy of the Black Hole A0620-00": line_7: McClintock, Remillard and Horne. Data under analysis. line_8: Program GO-3232 "Observations of X-ray Nova Muscae 1991": Panagia, Lund, line_9: Gilmozzi, Horne, Paresce, Valle, Schrader. line_10: paper submitted to Ap. J. line_11: Lambert has other GTO proposals for which no data has been received as line_12: yet. line_13: These projects are not related to the current proposal. ! question: 10 section: 1 line_1: Data analysis will be done using workstations at STSci, on a SUN Sparcstation line_2: at the University of Texas and on the STARLINK node at the University of line_3: Oxford. The University of Texas will provide facilities for a graduate student. ! !end of general form text general_form_address: lname: WOOD fname: JANET mi: H title: DR. category: PI inst: UNIVERSITY OF TEXAS addr_1: DEPARTMENT OF ASTRONOMY city: AUSTIN state: TX zip: 78712 country: USA phone: 512-471-3432 telex: 9108741351 from_date: 01-OCT-89 to_date: 30-SEP-92 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: GP-COM name_2: G61-29 name_3: WD1303+182 descr_1: A,151,161,906,909 pos_1: PLATE-ID=01PP, pos_2: RA = 13H 5M 42.84S +/- 0.027S, pos_3: DEC = +18D 1' 2.6" +/- 0.4" equinox: J2000 pm_or_par: Y pos_epoch_bj: B pos_epoch_yr: 1982.16 ra_pm_val: -0.023867 dec_pm_val: 0.0160 rv_or_z: Z=0.0 comment_1: THE CRITICAL S/N IS THAT IN THE comment_2: CONTINUUM AT 1396A, comment_3: NOT THAT IN THE 1240 LINE. fluxnum_1: 1 fluxval_1: V=15.8+/-0.2, E(B-V)=0.0+/-0.05 fluxnum_2: 2 fluxval_2: F-CONT(1396)=5.0+/-0.5E-15 fluxnum_3: 3 fluxval_3: F-LINE(1240)=5.0+/-0.05E-14 fluxnum_4: 4 fluxval_4: W-LINE(1240)=20+/-1 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: GP-COM config: FOS/BL opmode: ACQ/PEAK aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 10S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 2; req_2: GROUP 1-3 NO GAP; req_3: SPATIAL SCAN; req_4: CYCLE 2 / 1-3 ! linenum: 2.000 targname: GP-COM config: FOS/BL opmode: ACQ/PEAK aperture: 1.0 sp_element: MIRROR num_exp: 1 time_per_exp: 10S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 3; req_2: SPATIAL SCAN; ! linenum: 3.000 targname: GP-COM config: FOS/BL opmode: RAPID aperture: 4.3 sp_element: G130H wavelength: 1380 num_exp: 1 time_per_exp: 22020S s_to_n: 25 s_to_n_time: 22020S fluxnum_1: 2 priority: 1 param_1: READ-TIME=30 comment_1: THE CRITICAL S/N IS THAT comment_2: IN THE CONTINUUM AT 1396A, comment_3: NOT THAT IN THE 1240 LINE. ! ! end of exposure logsheet scan_data: line_list: 1 fgs_scan: cont_dwell: D dwell_pnts: 3 dwell_secs: 1.00 scan_width: 0.0000 scan_length: 2.8000 sides_angle: 90.0000 number_lines: 1 scan_rate: 0.0000 first_line_pa: 0.0000 scan_frame: S/C len_offset: 1.4 wid_offset: 0.0 ! line_list: 2 fgs_scan: cont_dwell: D dwell_pnts: 6 dwell_secs: 1.00 scan_width: 0.7000 scan_length: 3.5000 sides_angle: 90.0000 number_lines: 2 scan_rate: 0.0000 first_line_pa: 90.0000 scan_frame: S/C len_offset: 1.75 wid_offset: 0.35 ! ! end of scan data