! $Id: 5689,v 7.1 1994/07/27 20:23:40 pepsa Exp $ coverpage: title_1: A SEARCH FOR SILICON AND CARBON IN GP COM - CYCLE 4 CARRYOVER sci_cat: STELLAR ASTROPHYSICS sci_subcat: PECULIAR BINARIES proposal_for: GO/CAR cont_id: 3824 pi_title: DR. pi_fname: JANET pi_mi: H pi_lname: WOOD pi_inst: KEELE UNIVERSITY pi_country: UK pi_phone: 011-44-782-583326 hours_pri: 2.74 num_pri: 1 hrs: Y funds_amount: 76039 funds_length: 12 funds_date: OCT-92 pi_position: LECTURER off_fname: WATSON off_lname: FULLER off_title: DEPARTMENT HEAD off_inst: KEELE UNIVERSITY off_addr_1: DEPARTMENT OF PHYSICS off_city: KEELE off_country: UK off_phone: 011-44-782-583326 ! 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: KEELE UNIVERSITY country: UK esa: Y ! lname: MARSH fname: THOMAS title: DR. mi: R inst: UNIVERSITY OF SOUTHAMPTON 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: UNIVERSITY OF UTRECHT country: NETHERLANDS esa: Y ! ! end of general_form_proposers block general_form_text: ! question: 3 section: 1 line_1: We will take GHRS spectra of GP Com through the LSA. line_2: with the G140L grating. We will observe the range line_3: 1150-1430A in order to cover the SiIV 1394, 1403, line_4: and NV 1239, 1243 doublets with the highest sensitivity. We will also cover line_5: CIII 1175 and the SiIII complex at 1300. line_6: 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 400 seconds we will obtain line_12: information on orbital variations in the NV line and continuum. ! 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: 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 nodes at the Universities of line_3: Keele and Oxford. ! !end of general form text general_form_address: lname: WOOD fname: JANET mi: H title: DR. category: PI inst: KEELE UNIVERSITY addr_1: DEPARTMENT OF PHYSICS city: KEELE country: UK phone: 011-44-782-583341 telex: 36113 UNKLIB G from_date: 30-SEP-92 to_date: 30-SEP-97 ! ! 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(13961396)=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: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N1 num_exp: 1 time_per_exp: 135S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 2; req_2: GROUP 1-3 NO GAP; req_3: CYCLE 4 / 1-3 comment_1:step-time=15S expect 1000 counts ! linenum: 2.000 targname: GP-COM config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N1 num_exp: 1 time_per_exp: 714S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 3; comment_1:step-time=7S ! linenum: 3.000 targname: GP-COM config: HRS opmode: ACCUM aperture: 2.0 sp_element: G140L wavelength: 1290 num_exp: 13 time_per_exp: 411S s_to_n: 19 s_to_n_time: 5343S fluxnum_1: 2 priority: 1 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