! File: 4053C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:06:42:09 coverpage: title_1: HIGH RESOLUTION ULTRAVIOLET SPECTROSCOPY OF title_2: NOVA CYGNI 1992 IN THE NEBULAR PHASE sci_cat: STELLAR ASTROPHYSICS sci_subcat: HOT STARS proposal_for: GO/DD pi_title: DR. pi_fname: STEVEN pi_mi: N. pi_lname: SHORE pi_inst: COMPUTER SCIENCES CORPORATION pi_country: USA pi_phone: (301) 286-3748 keywords_1: NOVAE, MASS LOSS, NUCLEOSYNTHESIS hours_pri: 3.20 num_pri: 1 ! end of coverpage abstract: line_1: We propose to obtain intermediate dispersion GHRS line_2: observations of Nova Cygni 1992, one of the brightest line_3: classical novae of the century. With this high S/N data, line_4: we will study the shell dynamics, shell structure, and ejecta line_5: abundances during the optically thin nebular stages. ! ! end of abstract ! No general_form_proposers block records found general_form_text: question: 3 section: 1 line_1: Virtually all Galactic and Magellanic Cloud novae during the past line_2: three years have been observed by our group with IUE. Nova line_3: Cygni 1992 presents a new opportunity, to observe a bright nova at a line_4: later stage in its outbusrst than we have ever been able to study in line_5: the critically important ultraviolet plasma disgnositcs. ! question: 3 section: 2 line_1: These observations will be important for understanding line_2: the wealth of lower resolution outburst spectra of both line_3: galactic and extragalactic novae obtained with IUE, because the line_4: resolution available with the GHRS is considerably higher than any we line_5: have been able to obtain routinely (most novae have been observed only line_6: with the low dispersion, R=300, mode of IUE). line_7: The nova outburst is modeled via the thermonuclear runaway (TNR) line_9: picture. Matter accreted from a low mass companion on a degenerate line_10: star, a white dwarf for a classical nova, begins nucleosynthesis under line_11: extreme conditions. The release of energy by CNO processing initially line_12: produces no structural changes in the outer envelope of the white line_13: dwarf, but promotes mixing and increases the temperature gradient line_14: while the material remains degenerate. Until the temperature crosses ! question: 3 section: 3 line_1: the threshold for lifting the degeneracy, the rate of nuclear line_2: processing increases with consequent rise in the luminosity until the line_3: Eddington limit is reached. At about this time, an explosion results line_4: as the equation of state changes and subsequently a wind is initiated line_5: from the hot white dwarf envelope. Mass is ejected by a combination line_6: of gas and radiation pressure. line_8: The nebular stage is the most important one for the study of line_9: nucleosynthesis during the outburst. It occurs early enough during line_10: the ejecta expansion that little, if any, ambient material has been line_11: mixed into the ejecta. Therefore the abundances are those that line_12: were frozen in at the end of the TNR phase. It is very important line_13: to determine the physical conditions of the outburst, line_14: and especially to obtain accurate abundances and masses for line_15: the ejecta. These are the only window we have into the nuclear line_16: processing region that serves as the site of the outburst. line_17: The determination of abundances will place important line_18: constraints on the mixing and structure of the nuclear processing line_19: region during the early stages of the TNR. ! question: 3 section: 4 line_1: We have arranged continued groundbased coverage with the line_2: OSU 1.8m Perkins observatory and several other northern hemisphere line_3: observatories. We have been observing Nova Cyg 1992 line_4: with Voyager 1. Gamma Ray Observatory observations are line_5: being obtained as part of a TOO program. Groundbased line_6: infrared photometry is being obtained. We have proposed for line_7: ROSAT TOO time (Krautter,P.I./Heidelberg). Spectra will continue line_8: to be obtained with IUE for as long as possible, but we line_9: anticipate that by late April we will no longer to able to obtain line_10: high resolution observations. The LSA will be used for all line_12: accuracy. The ultraviolet spectrum accessible with the line_13: intermediate resolution GHRS gratings covers all significant line_14: ions for abundance determinations: G160M: N V line_15: 1240, O I 1300, C II 1335, Si IV/O IV/S IV 1400, N IV line_16: 1490, C IV 1550, Ne 1600, He II 1640, O III] 1665, N III] 1750, line_17: Si III] 1890, C III] 1910; G200M: C II 2320. line_18: We will use standard FP-SPLIT with half-stepping. ! question: 3 section: 5 line_1: We will use the intercombination lines, like N III] and Si line_2: III]/C III] for determining density and shell structure. line_3: Individual emission knots will be easily resolved in these data, line_4: and with a S/N superior to any ever obtained on a classical nova line_5: during outburst in the UV. We will use permitted lines as line_6: diagnostics of dynamics, and by combining the various ionization line_7: stages, especially of nitrogen, we will determine abundance in the line_8: ejecta. The observations will be timed to coincide with the line_9: second imaging observation under an unrelated HST program. One line_10: sequence on the target will suffice for all of the line_11: information necessary for density diagnosis and abundances, line_12: as well as velocity information. ! question: 4 section: 1 line_1: GHRS will provide the spectral resolution, sensitivity, line_2: and dynamic range to record the ultraviolet spectra of this nova line_3: at the nebular stage of the outburst with a precision and spectral line_4: resolution unobtainable with IUE. The most important feature of line_5: GHRS spectra is their dynamic range, with which we will be line_6: able to observe both strong intercombination and permitted lines, line_7: and weak coronal and trace ionic species lines. We will be able to line_8: use the C III] , N III], and Si III] lines as nebular diagnostics line_9: and dynamics and abundances using the C IV and He II permitted line_10: lines, long past the stage at which IUE observations cease to be line_11: feasible. Of special importance is the study of weak high line_12: ionization lines of coronal species; these cannot be obtained line_13: with IUE. We will use the N III] and O III] line ratios for the line_14: determination of the electron density independent of the Si III] line_15: and C III] lines. These will also provide the necessary line_16: information on the O and N abundances to complement the low line_17: resolution observations we will continue to make with IUE. line_18: Finally He II and C IV will provide important dynamical Doppler line_19: mapping of the excitation conditions in the ejecta since they are line_20: the only strong permitted lines in the spectrum. ! question: 5 section: 1 line_1: We are requesting one sequence of observations, line_2: during the second imaging visit to Nova Cyg 1992 for line_3: These observations will be coordinated with IUE in order to obtain line_4: simultaneous low resolution data for flux calibration. line_6: We know the UV fluxes and rate of decline, and also have line_7: UV lightcurves of similar novae from IUE, all of which indicate line_8: that the nova will be accessible with the GHRS at medium line_9: resolution through at least Autumn 1992. For any time line_10: before about Sept. 1992, 10 minute exposures at each line_11: wavelength should produce a S/N of more than 30 in the lines and line_12: about 5 in the continuum. We have resourced the proposal and line_13: obtain 3.5 hours of total time. ! question: 7 section: 1 line_1: The calibration and reduction of the GHRS spectra line_2: will be accomplished with routines developed for the purpose line_3: at GSFC. All IUE comparisons will be iundertaken at line_4: Goddard using GSFC and VILSPA data. line_5: Emission lines will be analyzed with respect to fluxes, line line_6: profiles, and radial velocities. Corrections for extinction will line_7: be applied. The various ionization stages of key species (C, N, line_8: O, Mg, Si, Fe) will be studied to estimate the excitation, mass, line_9: and kinetic energy of the ejecta, providing a key test of nuclear line_10: processing models for the outburst. Presently undetected coronal line_11: lines will be searched for, and fluxes, or at least upper limits, line_12: will be determined. ! question: 9 section: 1 line_1: Shore (PI), Sonneborn, and Starrfield have been granted time line_2: for a GO target of opportunity proposal in cycle 2 to observe line_3: LMC novae with the GHRS. Shore (PI), Starrfield, and Sonneborn line_4: were granted DDT/TOO time for observations of Nova LMC 1991 which line_5: failed because of the failure of the GHRS SDF. There is line_6: currently no nova TOO program and the present request is line_7: for observations at the end of cycle 1. ! question: 10 section: 1 line_1: Reduction software, computers, modeling programs, line_2: preparation of manuscripts, support of publication costs. ! question: 12 section: 1 line_1: We will use noninteractive target acquisition for Nova line_2: Cyg 1992. Since the satellite will already be pointing at line_3: the nova for imaging, a slew between SI apertures is all that is line_4: required. However, novae are transient phenomena, and we will use line_5: IUE low resolution fluxes to predict the FOC and GHRS count rates line_6: and will provide these to OCC at least three weeks before the line_7: scheduled observations to facilitate SMS production. We expect line_8: to be able to observe the nova with IUE at low resolution for line_9: about one year. The observations will be performed using line_10: the LSA in coarse track. ! !end of general form text general_form_address: lname: SHORE fname: STEVEN mi: N. title: DR. category: PI inst: COMPUTER SCIENCES CORPORATION addr_1: CODE 681 GODDARD SPACE FLIGHT CENTER city: GREENBELT state: MD zip: 20771 country: USA phone: (301) 286-3748 ! lname: STARRFIELD fname: SUMNER mi: G. title: DR. inst: ARIZONA STATE UNIVERSITY addr_1: DEPT. OF PHYS. AND ASTRONOMY addr_2: ARIZ. STATE UNIV. city: TEMPE state: AZ zip: 85287 country: USA phone: (602) 965-7569 ! lname: SONNEBORN fname: GEORGE title: DR. inst: LABORATORY FOR ASTRONOMY AND SOLAR PHYSICS/NASA addr_1: CODE 681 addr_2: GODDARD SPACE FLIGHT CENTER city: GREENBELT state: MD zip: 20771 country: USA phone: (301) 286-3665 ! lname: AKE fname: THOMAS mi: B. title: DR. inst: COMPUTER SCIENCES CORPORATION addr_1: CODE 681 addr_2: GODDARD SPACE FLIGHT CENTER city: GREENBELT state: MD zip: 20771 country: USA phone: (301)286-3924 ! lname: GONZALEZ-RIESTRA fname: ROSARIO title: DR. inst: IUE/VILSPA addr_1: IUE SATELLITE TRACKING STATION addr_2: APARTADO 54065 city: MADRID 28080 country: SPAIN ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: N-CYG-1992 descr_1: CENTRAL STAR pos_1: RA = 20H 29M 07.03S +/- 0.1S, pos_2: DEC = 52D 27' 44.0" +/- 0.1", equinox: 1950.0 pm_or_par: NO fluxnum_1: 1 fluxval_1: F-LINE(1240)=6.0E-13 fluxnum_2: 2 fluxval_2: F-LINE(1550)=8.0E-13 fluxnum_3: 3 fluxval_3: F-LINE(1640)=1.0E-13 fluxnum_4: 3 fluxval_4: F-LINE(1900)=4.0E-13 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: N-CYG-1992 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 1.8S priority: 1 param_1: SEARCH-SIZE=3 param_2: FAINT=100 req_1: ONBOARD ACQ FOR 2-37; req_2: CYCLE 1/ 1-37 ! linenum: 2.000 targname: N-CYG-1992 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 9.2S priority: 1 req_2: CYCLE 1 ! linenum: 10.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G200M wavelength: 1910 num_exp: 1 time_per_exp: 30S priority: 1 param_1: STEP-PATT=4 req_1: CALIB FOR 11; req_2: SEQ 10-11 NO GAP; req_3: CYCLE 1 comment_1: WAVELENGTH CALIBRATION LINE 11 comment_2: TO INCLUDE SPECTRUM Y BALANCE. ! linenum: 11.000 targname: N-CYG-1992 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ^ wavelength: 1900.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 31.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1500 num_exp: 1 time_per_exp: 30S priority: 1 param_1: STEP-PATT=4 req_1: CALIB FOR 32; req_2: SEQ 31-37 NO GAP; req_3: CYCLE 1/ 31-37 comment_1: WAVELENGTH CALIBRATIONS LINES 32-37, comment_2: TO INCLUDE SPECTRUM Y BALANCE. ! linenum: 32.000 targname: N-CYG-1992 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1240 num_exp: 1 time_per_exp: 10M s_to_n: 15 fluxnum_1: 1 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 34.000 targname: ^ config: HRS opmode: ACCUM aperture: 2.0 sp_element: ^ wavelength: 1400.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 35.000 targname: N-CYG-1992 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1550.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 36.000 targname: ^ config: HRS opmode: ACCUM aperture: 2.0 sp_element: ^ wavelength: 1487.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 36.001 targname: N-CYG-1992 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1604.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 36.002 targname: ^ config: HRS opmode: ACCUM aperture: 2.0 sp_element: ^ wavelength: 1640.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! linenum: 37.000 targname: ^ config: HRS opmode: ACCUM aperture: 2.0 sp_element: ^ wavelength: 1750.0 num_exp: 1 time_per_exp: 10M s_to_n: 10 fluxnum_1: 2 priority: 1 param_1: STEP-PATT=4, param_2: FP-SPLIT=TWO param_3: COMB=TWO ! ! end of exposure logsheet ! No scan data records found