! File: 4263C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:19:31:14 coverpage: title_1: NLTE SPECTRAL ANALYSIS OF THREE PG1159 STARS: title_2: FINDING THE BOUNDARIES OF THE GW VIR INSTABILITY STRIP CYCLE3 MEDIUM sci_cat: HOT STARS sci_subcat: WHITE DWARFS proposal_for: GO pi_fname: ULRICH pi_lname: HEBER pi_inst: UNIVERSITAT ERLANGEN-NURNBERG pi_country: GERMANY hours_pri: 9.48 num_pri: 3 fos: Y off_fname: IRMELA off_lname: BUES off_title: PROFESSOR off_inst: 5578 off_addr_1: DR. REMEIS-STERNWARTE off_addr_2: ASTRONOMISCHES INSTITUT DER UNIVERSITAET ERLANGEN-NUERNBERG off_city: D-8600 BAMBERG off_country: GERMANY off_phone: 499519522213 ! end of coverpage abstract: line_1: The PG1159 stars form a new class of hydrogen deficient pre white dwarfs (PWD) line_2: representing the hottest stage (Teff>=100,000 K) of PWD evolution. First quan- line_3: titative spectral analyses have been carried out by the proposers. The proto- line_4: type PG1159-035 has been analysed from the HST-FOS spectrum with unprecedented line_5: precision. It has been shown that these stars have atmospheres dominated by line_6: carbon and helium with a significant amount of oxygen present. Extreme mass loss line_7: has removed the H rich and most of the He rich layers. Such a mass loss event line_8: has been observed in Lo4. About every other member of the PG1159 stars is a non- line_9: radial, multi-periodic g-mode pulsator driven by cyclic ionisation of C and O. line_10: Modelling of the pulsations allows the stellar mass to be determined very line_11: accurately and the stellar interior to be probed (asteroseismology). A line_12: prerequisite for such modelling is a precise determination of the photospheric line_13: parameters. We propose to obtain UV observations of three additional PG1159 line_14: stars (one pulsator and two non-pulsators) in addition to the (pulsating) line_15: prototype in order to trace differences in photospheric parameters and line_16: composition. The spectra will be analysed with new highly-sophisticated NLTE line_17: line blanketed model atmospheres, which allow the synthetic spectrum to be line_18: calculated and line blending of iron group elements to be included self- line_19: consistently. The results will allow us to determine the position of the new line_20: instability strip (defined by the pulsating PG1159 stars) in the HRD. ! ! end of abstract general_form_proposers: lname: HEBER fname: ULRICH title: PI inst: UNIVERSITAT ERLANGEN-NURNBERG country: GERMANY esa: Y ! lname: DREIZLER fname: STEFAN inst: UNIVERSITAT ERLANGEN-NURNBERG country: GERMANY esa: Y ! lname: RAUCH fname: THOMAS inst: UNIVERSITAT KIEL country: GERMANY esa: Y ! lname: WERNER fname: KLAUS inst: UNIVERSITAT ERLANGEN-NURNBERG country: GERMANY esa: Y ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: The Faint Object Spectrograph (FOS) shall be used to perform ultraviolet line_2: spectroscopy of three PG1159 stars in exactly the same way as for PG1159-035 line_3: (GO-proposal 2741 carried out in cycle 1): line_4: 1. PG1520+525 line_5: 2. PG1707+427 line_6: 3. PG1424+535 line_7: One low resolution spectrum shall be obtained for each of these objects (long line_8: slit, 0.25*2 arcsec) with the blue detector and the G130H grating, namely in line_9: the wavelength range 115nm-160nm, covering the NV resonance doublet, line_10: OV 137.1nm, and several CIV and OVI lines. ! question: 4 section: 1 line_1: Optical spectra of high S/N ratio (near 100) have been obtained at the DSAZ line_2: 3.5m telescope, covering the wavelength range from 330nm to 700nm at a spectral line_3: resolution of 0.2nm. These spectra have been used for a NLTE model atmosphere line_4: analysis (Werner, Heber & Hunger 1991; Werner & Heber 1991a). line_5: Low resolution IUE spectra are available from the IUE archive, however, these line_6: spectra are of insufficient dispersion for the proposed analysis. On the other line_7: hand, the targets are too faint to be observed with IUE in the high resolution line_8: mode. line_9: Therefore, the UV lines of crucial importance for the high precision analysis line_10: (see Scientific Justification) can only be observed with HST. ! question: 7 section: 1 line_1: Data reduction will be carried out using the IRAF+STSDAS program package at line_2: the ESA-ECF, Garching. The software will also be installed on the Bamberg node line_3: of the German Astronet (DAN). Observed line profiles will be compared to line_4: theoretical predictions in order to derive effective temperature, surface line_5: gravity, and abundances. The model atmosphere calculations described in the line_6: Scientific Justification will be extended further. line_7: Numerical calculations are carried out using the Cray YMP/EL computer of the line_8: "Rechenzentrum der Universitaet Erlangen-Nuernberg", the Cray YMP of the line_9: "Bayerischer Landesvektorrechner in Muenchen" and the Cray X-MP computer of the line_10: "Rechenzentrum der Universitaet Kiel". ! question: 9 section: 1 line_1: Cycle 1: ID 2741: NLTE SPECTRAL ANALYSIS OF THE PRE WHITE DWARF PG1159-035 line_2: We have obtained a FOS spectrum of PG1159-035, the prototype of the line_3: PG1159 class. Results of the model atmosphere analysis have yielded the line_4: atmospheric parameters with high precision (see section 1 and the line profile line_5: fits in Fig. 1 and 2.). This observation is closely related to this proposal, line_6: since one of its targets (PG1520+525) is spectroscopically similar to line_7: PG1159-035 (in the optical), however, it does not pulsate. The spectrum line_8: obtained for ID 2741 (in cycle 1) will serve as a reference spectrum line_9: for a differential analysis of the three targets proposed here. line_10: Differences among the pulsator--non-pulsator pairs in the UV spectra line_11: will help to determine the position of the GW Vir instability strip in the HRD. line_12: Cycle 2: ID 3513: Non-LTE analysis of the population II post AGB stars ROB162 line_13: and K648 (not related to this proposal) line_14: ID 2741: A FOS spectrum with the blue detector, grating G130H and the 0.25"*1.4" line_15: aperture has been obtained on May 8, 1992. It has been analysed line_16: by comparing the normalized spectrum to synthetic spectra calculated line_17: from our NLTE model grid. The effective temperature has been line_18: determined with unprecedented accuracy (better than 3%) to be line_19: 140,000K (see Fig. 1 and 2 attached to the Scientific justification). line_20: Due to better known Teff and the larger number of spectral lines the line_21: analysis will give much more reliable abundances that the early results line_22: based on optical spectroscopy. line_23: ID 3513: The observations are currently in the process of scheduling. ! question: 10 section: 1 line_1: Computer resources: line_2: i) Micro VAX 3300 + 2 VAX Station 3100 of the DAN node Bamberg line_3: ii) Cray YMP/EL of the Universitaet Erlangen-Nuernberg line_4: iii) Cray YMP, Landesvektorrechner Muenchen line_5: iv) VAX 8550 of the "Rechenzentrum der Universitaet Kiel" line_6: v) Cray X-MP of the "Rechenzentrum der Universitaet Kiel" line_7: vi) MODCOMP-Unix-Workstation of the Physics Department of line_8: Universitaet Kiel line_9: Research assistance: Dr. H. Drechsel (system manager of the Bamberg DAN node), line_10: Dipl.Ing. G.Jonas (Kiel, data reduction specialist), ! !end of general form text general_form_address: lname: HEBER fname: ULRICH category: PI inst: Universitat Erlangen-Nurnberg addr_1: DR. REMEIS-STERNWARTE addr_2: ASTRONOMISCHES INSTITUT DER UNIVERSITAET ERLANGEN-NUERNBERG city: D-8600 BAMBERG country: GERMANY phone: 499519522214 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: PG1520+525 descr_1: A,176 pos_1: RA = 15H 21M 46.542S +/- 0.013S, pos_2: DEC = +52D 22' 3.85" +/- 0.2", pos_3: PLATE-ID=01RT equinox: 2000 pos_epoch_bj: J fluxnum_1: 1 fluxval_1: V = 15.5 +/- 0.2, TYPE=DOZ, E(B-V)=0.00 fluxnum_2: 2 fluxval_2: F-CONT(1370) = 5.4 +/- 1.0 E-13 fluxnum_3: 3 fluxval_3: F-CONT(1550) = 3.2 +/- 0.6 E-13 fluxnum_4: 4 fluxval_4: F-CONT(1240) = 7.5 +/- 1.0 E-13 ! targnum: 2 name_1: PG1424+535 descr_1: A,176 pos_1: RA = 14H 25M 55.412S +/- 0.013S, pos_2: DEC = +53D 15' 24.76" +/- 0.2", pos_3: PLATE-ID=01AL equinox: 2000 pos_epoch_bj: J fluxnum_1: 1 fluxval_1: V = 16.2 +/- 0.2, TYPE=DOZ, E(B-V)=0.00 fluxnum_2: 2 fluxval_2: F-CONT(1370) = 3.7 +/- 0.7 E-13 fluxnum_3: 3 fluxval_3: F-CONT(1550) = 2.2 +/- 0.4 E-13 fluxnum_4: 4 fluxval_4: F-CONT(1240) = 5.1 +/- 1.0 E-13 ! targnum: 3 name_1: PG1707+427 descr_1: A,176 pos_1: RA = 17H 8M 47.697S +/- 0.013S, pos_2: DEC = +42D 40' 59.95" +/- 0.2", pos_3: PLATE-ID=009J equinox: 2000 pos_epoch_bj: J fluxnum_1: 1 fluxval_1: V = 16.4 +/- 0.4, TYPE=DOZ, E(B-V)=0.00 fluxnum_2: 2 fluxval_2: F-CONT(1370) = 1.5 +/- 0.3 E-13 fluxnum_3: 3 fluxval_3: F-CONT(1550) = 0.8 +/- 0.2 E-13 fluxnum_4: 4 fluxval_4: F-CONT(1240) = 2.1 +/- 0.4 E-13 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: PG1520+525 config: FOS/BL opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 1.4S priority: 1 req_1: CYCLE 3; req_2: ONBOARD ACQ FOR 1.100 ! linenum: 1.100 targname: PG1520+525 config: FOS/BL opmode: ACQ/PEAK aperture: 0.25X2.0 sp_element: MIRROR num_exp: 1 time_per_exp: 1.4S priority: 1 param_1: TYPE=UP req_1: CYCLE 3; req_2: SPATIAL SCAN; req_3: ONBOARD ACQ FOR 1.200 ! linenum: 1.200 targname: PG1520+525 config: FOS/BL opmode: ACCUM aperture: 0.25X2.0 sp_element: G130H wavelength: 1200-1600 num_exp: 1 time_per_exp: 112M s_to_n: 100 fluxnum_1: 4 priority: 1 req_1: CYCLE 3 ! linenum: 2.000 targname: PG1424+535 config: FOS/BL opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 2.0S priority: 1 req_1: CYCLE 3; req_2: ONBOARD ACQ FOR 2.100 ! linenum: 2.100 targname: PG1424+535 config: FOS/BL opmode: ACQ/PEAK aperture: 0.25X2.0 sp_element: MIRROR num_exp: 1 time_per_exp: 2.0S priority: 1 param_1: TYPE=UP req_1: CYCLE 3; req_2: SPATIAL SCAN; req_3: ONBOARD ACQ FOR 2.200 ! linenum: 2.200 targname: PG1424+535 config: FOS/BL opmode: ACCUM aperture: 0.25X2.0 sp_element: G130H wavelength: 1200-1600 num_exp: 1 time_per_exp: 100M s_to_n: 80 fluxnum_1: 4 priority: 1 req_1: CYCLE 3 ! linenum: 3.000 targname: PG1707+427 config: FOS/BL opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 4.0S priority: 1 req_1: CYCLE 3; req_2: ONBOARD ACQ FOR 3.100 ! linenum: 3.100 targname: PG1707+427 config: FOS/BL opmode: ACQ/PEAK aperture: 0.25X2.0 sp_element: MIRROR num_exp: 1 time_per_exp: 5.0S priority: 1 param_1: TYPE=UP req_1: CYCLE 3; req_2: SPATIAL SCAN; req_3: ONBOARD ACQ FOR 3.200 ! linenum: 3.200 targname: PG1707+427 config: FOS/BL opmode: ACCUM aperture: 0.25X2.0 sp_element: G130H wavelength: 1200-1600 num_exp: 1 time_per_exp: 172M s_to_n: 80 fluxnum_1: 4 priority: 1 req_1: CYCLE 3 ! ! end of exposure logsheet scan_data: line_list: 1.100,2.100,3.100 fgs_scan: cont_dwell: D dwell_pnts: 7 dwell_secs: 1.00 scan_width: 0.0000 scan_length: 0.4000 sides_angle: 90.0000 number_lines: 1 scan_rate: 0.0000 first_line_pa: 90.0000 scan_frame: S/C len_offset: 0.2 wid_offset: 0. ! ! end of scan data