! File: 3496C.PROP ! Database: PEPDB ! Date: 19-FEB-1994:09:53:19 coverpage: title_1: AN ULTRAVIOLET ATLAS OF SIRIUS: CONSTRAINING MODEL STELLAR title_2: ATMOSPHERES sci_cat: STELLAR ASTROPHYSICS sci_subcat: STELLAR ATMOSPHERES proposal_for: GO pi_fname: GLENN pi_mi: M pi_lname: WAHLGREN pi_inst: COMPUTER SCIENCES CORPORATION pi_country: USA pi_phone: 301-286-4533 hours_pri: 2.45 num_pri: 1 hrs: Y funds_amount: 45679 funds_length: 12 off_fname: ROSELLE off_lname: HARDE off_title: SR. CONTRACTS ADMIN. off_inst: COMPUTER SCIENCES CORPORATION off_addr_1: SYSTEM SCIENCES DIVISION off_addr_2: 4061 POWDER MILL ROAD off_city: CALVERTON off_state: MD off_zip: 20705 off_country: USA off_phone: (301) 572-3637 ! end of coverpage abstract: line_1: The GHRS will be utilized to obtain a high signal-to-noise, intermediate line_2: resolution (R=25000), ultraviolet spectrum of the bright A1V star Sirius line_3: for the wavelength range 1280 to 3180 A. Such a spectrum will place line_4: severe constraints upon flux distributions generated by stellar model line_5: atmospheres. Modeled flux distributions consistently over-estimate the line_6: ultraviolet flux as a result of an incomplete treatment of the atomic line_7: line opacity. The modeled effective temperatures are therefore too hot line_8: and systematic errors propagate into subsequent analyses, such as line_9: for elemental abundances. Treatment of the ultraviolet opacity is line_10: especially poor below 2000A. Of particular interest are the singly line_11: and doubly ionized elements of the iron-group (Z=21-28) since they line_12: represent a vast number of discrete transitions that are responsible line_13: for the bulk of the ultraviolet opacity in warm stars. The spectral line_14: atlas obtained for Sirius will provide the high quality line profiles line_15: over an extended wavelength range that are necessary for determining line_16: consistent atomic parameters and elemental abundances. Even though line_17: Sirius has been well studied in the visual region the majority of its line_18: flux and the dominant opacity species lie in the ultraviolet. Many line_19: elemental species that have few or no transitions in the visual region line_20: will have their abundances determined for the first time. ! ! end of abstract general_form_proposers: lname: WAHLGREN fname: GLENN title: PI mi: M inst: COMPUTER SCIENCES CORPORATION country: USA ! lname: LECKRONE fname: DAVID mi: S inst: NASA, GODDARD SPACE FLIGHT CENTER country: USA ! lname: KURUCZ fname: ROBERT mi: L inst: SMITHSONIAN ASTROPHYSICAL OBSERVATORY country: USA ! lname: JOHANSSON fname: SVENERIC mi: G inst: UNIVERSITY OF LUND country: SWEDEN esa: Y ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: The GHRS will be used to obtain high signal-to-noise (200-300) line_2: intermediate resolution (R=25000) spectra of the bright A1V line_3: star Sirius. Spectra of such a high photometric quality are line_4: necessary to constrain stellar model atmosphere ultraviolet line_5: fluxes and provide data from which atomic parameters can be line_6: derived. Three gratings (G160M, G200M, G270M) will be used to line_7: obtain spectra from 1280 to 3180A. Longward of 3200A the line_8: second order spectrum of the G270M grating contaminates the line_9: first-order spectrum. The small science aperture (SSA) will line_10: provide the maximum spectral resolution. A step-pattern of line_11: 5 will be used with the G160M and G200M gratings, and 11 for line_12: the G270M. line_13: Exposure times are calculated by the equation (S/N)**2 = line_14: (flux)*(sensitivity)*(exp time), as discussed in the GHRS line_15: Instrument Handbook. Stellar fluxes were obtained from IUE line_16: low-dispersion spectra. Post-launch instrument sensitivities line_17: and LSA to SSA conversion factors were taken from the HST line_18: Cycle 2 Proposal Submissions, Updated Technical Information line_19: document (23 May 1991). The throughput loss due to the line_20: primary mirror spherical aberration is accounted for in these line_21: numbers. The table below presents for each WSCAN: grating, line_22: wavelength coverage, the number of wavelength settings, line_23: exposure time per setting, S/N per quarter-stepped data ! question: 3 section: 2 line_1: point, and the total exposure time. The range in S/N level line_2: originates from a varying stellar flux and instrument line_3: sensitivity across the wavelength interval of the WSCAN mode line_4: observation. line_5: grating wavelength # settings exp time/ S/N exp time line_6: . interval setting line_7: . (A) (sec) (min) line_8: G160M 1281-1502 7 327 200-300 38.15 line_9: G160M 1500-2090 19 218 250-350 69.03 line_10: G200M 2088-2193 3 109 250-300 5.45 line_11: G270M 2191-3180 25 77 200-300 32.08 line_12: . total 136.80 (2.41hr) ! question: 4 section: 1 line_1: In order to constrain the flux predicted by stellar model line_2: atmospheres and improve our atomic data bases high photometric line_3: quality spectral data are needed. The superior quality of the line_4: proposed uv spectrum of Sirius will provide the required data. line_5: Our analysis of Science Assessment Observation GHRS echelle and line_6: first-order grating spectra of the chemically peculiar star line_7: chi Lupi has demonstrated that the current status of atomic line_8: data for uv transitions of iron-peak elements is inadequate for line_9: detailed line profile analysis. For elements outside the iron-group line_10: the situation is even worse. Two decades of experience with line_11: uv spectra has improved atomic data for a limited number of line_12: strong, isolated transitions, but the data quality has proven line_13: inadequate in reducing the errors. In its high-dispersion mode line_14: the IUE satellite resolution is 0.6A with S/N levels typically line_15: less than 20, inadequate in both respects for detailed line line_16: profile analysis. The Copernicus uv spectrum of Sirius, obtained line_17: at a spectral resolution of 0.1A (Rogerson 1987, ApJS 63, 369), line_18: contains no data shortward of 1650A and also does not provide line_19: the requisit photometric quality to constrain the flux below line_20: 2000A, where the discrepancy between the models and observations line_21: is most severe. The spectral resolution offered by the GHRS line_22: first-order gratings is better than 0.1A at all wavelengths. ! question: 5 section: 1 line_1: At the time of the phase 2 submission for cycle 2 proposals line_2: it is anticipated that the GHRS target acquisition option of line_3: Return to Brightest Point (RBP) will be ready for GO use around line_4: October 1992. If it is anticipated that this date is to be line_5: pushed back further than December of 1992 I would recommend line_6: that an alternate target acquisition procedure be considered line_7: before the target enters the solar avoidance zone. line_8: This proposal also requests the use of GHRS Small Science Aper. line_9: peakup, by a spiral search technique currently used in the line_10: Large Science Aperture. Commanding software for the SSA line_11: peakup mode will probably not be ready for use until after line_12: the RBP software is implemented. In the next couple of months line_13: normal use of the GHRS may prove the SSA peakup unnecessary line_14: for this program, due to software changes that have been line_15: implemented but not yet tested. Therefore, the scheduling of line_16: this program should not be delayed on account of SSA peakup line_17: unavailability. In all likelyhood SSA peakup will not be line_18: required and it can then be removed from the exposure logsheet, line_19: resulting in a savings of spacecraft time. The P.I. should line_20: be consulted prior to scheduling. ! question: 7 section: 1 line_1: All data will be reduced at Goddard Space Flight Center (GSFC) line_2: using software developed by the GHRS IDT. The wavelength line_3: scale will be calibrated using the default calibration lamp line_4: exposures which will provide an accuracy better than 1/2 diode. line_5: The absolute scale will be set by laboratory wavelengths. line_6: The spectra will be scrutinized for blemishes and detector line_7: granularity, although the latter is fairly well behaved in line_8: the D2 detector. ATLAS-based LTE model atmospheres and spectrum line_9: synthesis codes, along with a massive atomic data base required line_10: for calculations, are currently in use at GSFC and the Center line_11: for Astrophysics. Data analysis is comprised of several line_12: components that can be conducted simultaneously. The initial line_13: comparison of the synthetic spectrum to the data will highlight line_14: and quantify the spectral regions which have flux discrepancies. line_15: Improvements to the fit will involve changes to the stellar line_16: model, the Teff in particular, and better knowledge of the line_17: uv line opacity. All unidentified and discordant line profile line_18: fits will be catalogued, emphasising the iron-peak elements line_19: which are the dominant source of uv opacity. Atomic structure line_20: codes running at CfA and the Univ. of Lund will revise the line_21: atomic parameters, constrained by the observations. For some line_22: elements it may be necessary to directly measure branching line_23: ratios with the new LUND Fourier Transform Spectrometer, ! question: 7 section: 2 line_1: from which gf values can be calculated. With an updated line_2: atomic data base new ATLAS opacity distribution functions will line_3: be created. The model atmosphere for Sirius will then be line_4: reconverged. Remaining flux descrepancies will be investigated line_5: and may signal previously unsuspected problems associated with line_6: stellar atmospheric modeling. As Sirius is often used as an line_7: elemental abundance standard for warm stars we will determine line_8: abundances for those elements that have few or no transitions line_9: in the visual spectral region. The entire uv spectrum will line_10: be published as an atlas with accurate line identifications line_11: that will serve the astronomical community for years to come. ! question: 9 section: 1 line_1: Described in phase I proposal. ! question: 10 section: 1 line_1: CSC personnel have access to VAX mainframe computers and line_2: peripherals at several sites for basic data reduction and line_3: analysis. Data analysis software, including STSDAS and line_4: spectral analysis packages based on the Interactive Data Language line_5: (IDL) are also available. There are a large number of astronomers line_6: at CSC available for expert advice to an investigator on line_7: observational techniques, detector calibration, data analysis, line_8: and theoretical modeling. CSC also provides a pool of research line_9: assistants and data technicians as well as administrative and line_10: secretarial support for research programs. Dr. Wahlgren has line_11: access to GHRS IDT software and office space at GSFC, where line_12: he interacts with GHRS team members. The Co-I's home line_13: institutions supply them with access to computing facilities. ! !end of general form text general_form_address: lname: WAHLGREN fname: GLENN mi: M. category: PI inst: COMPUTER SCIENCES CORPORATION addr_1: CODE 681 addr_2: GSFC city: GREENBELT state: MD zip: 20771 country: USA phone: 301-286-4533 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: HD48915 name_2: ALPHA-CMA name_3: SIRIUS descr_1: A,123 pos_1: RA=06H45M08.869S +/- 0.2S, pos_2: DEC=-16D42'58.00" +/- 0.2" equinox: J2000 pm_or_par: Y pos_epoch_yr: 2000.00 ra_pm_val: -0.039677 ra_pm_unct: 0.000696 dec_pm_val: -1.2100 dec_pm_unct: 0.0100 an_prlx_val: 0.3780 an_prlx_unct: 0.0100 rv_or_z: V=-8 acqpr_1: COMP comment_1: COORDINATES FROM TYCHO INPUT comment_2: CATALOGUE: SPECTROSCOPIC BINARY fluxnum_1: 1 fluxval_1: V=-1.46+/-.05, TYPE=A1V fluxnum_2: 2 fluxval_2: F-CONT(1300)=6.1E-9 fluxnum_3: 3 fluxval_3: F-CONT(1500)=1.6E-8 fluxnum_4: 4 fluxval_4: F-CONT(1700)=2.1E-8 fluxnum_5: 5 fluxval_5: F-CONT(1900)=1.8E-8 fluxnum_6: 6 fluxval_6: F-CONT(2100)=1.7E-8 fluxnum_7: 7 fluxval_7: F-CONT(2300)=1.4E-8 fluxnum_8: 8 fluxval_8: F-CONT(2500)=1.2E-8 fluxnum_9: 9 fluxval_9: F-CONT(2700)=1.1E-8 fluxnum_10: 10 fluxval_10: F-CONT(2900)=1.1E-8 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 3.400 targname: HD48915 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 27.4S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, param_4: MAP=END-POINT req_1: ONBOARD ACQ FOR 3.45; comment_1: STEP-TIME=0.2 SEC ! linenum: 3.450 targname: HD48915 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 20.4S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 3.500 comment_1: STEP-TIME=0.2 SEC ! linenum: 3.500 targname: HD48915 config: HRS opmode: WSCAN aperture: 0.25 sp_element: G270M wavelength: 2683-3180 num_exp: 1 time_per_exp: 626S s_to_n: 200 fluxnum_1: 7 fluxnum_2: 8 fluxnum_3: 9 fluxnum_4: 10 priority: 1 param_1: FP-SPLIT=STD, param_2: STEP-PATT=11, param_3: WAVE-STEP=41 ! linenum: 4.500 targname: HD48915 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 27.4S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, param_4: MAP=END-POINT req_1: ONBOARD ACQ FOR 4.6; req_2: CYCLE 2 / 3.4-8.0 comment_1: STEP-TIME=0.2 SEC ! linenum: 4.600 targname: HD48915 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 20.4S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 5.000 comment_1: STEP-TIME=0.2 SEC ! linenum: 5.000 targname: HD48915 config: HRS opmode: WSCAN aperture: 0.25 sp_element: G160M wavelength: 1281-1502 num_exp: 1 time_per_exp: 1742S s_to_n: 200 fluxnum_1: 2 fluxnum_2: 3 priority: 1 param_1: FP-SPLIT=STD, param_2: STEP-PATT=5, param_3: WAVE-STEP=31 ! linenum: 5.500 targname: HD48915 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 27.4S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, param_4: MAP=END-POINT req_1: ONBOARD ACQ FOR 5.6; comment_1: STEP-TIME=0.2 SEC ! linenum: 5.600 targname: HD48915 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 20.4S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 6.000 comment_1: STEP-TIME=0.2 SEC ! linenum: 6.000 targname: HD48915 config: HRS opmode: WSCAN aperture: 0.25 sp_element: G160M wavelength: 1500-1779 num_exp: 1 time_per_exp: 981S s_to_n: 200 fluxnum_1: 3 fluxnum_2: 4 fluxnum_3: 5 priority: 1 param_1: FP-SPLIT=STD, param_2: STEP-PATT=5, param_3: WAVE-STEP=31 ! linenum: 6.400 targname: HD48915 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 27.4S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, param_4: MAP=END-POINT req_1: ONBOARD ACQ FOR 6.45; comment_1: STEP-TIME=0.2 SEC ! linenum: 6.450 targname: HD48915 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 20.4S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 6.500 comment_1: STEP-TIME=0.2 SEC ! linenum: 6.500 targname: HD48915 config: HRS opmode: WSCAN aperture: 0.25 sp_element: G160M wavelength: 1779-2090 num_exp: 1 time_per_exp: 1198S s_to_n: 200 fluxnum_1: 3 fluxnum_2: 4 fluxnum_3: 5 priority: 1 param_1: FP-SPLIT=STD, param_2: STEP-PATT=5, param_3: WAVE-STEP=31 ! linenum: 6.600 targname: HD48915 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 27.4S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, param_4: MAP=END-POINT req_1: ONBOARD ACQ FOR 6.7; comment_1: STEP-TIME=0.2 SEC ! linenum: 6.700 targname: HD48915 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 20.4S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 7.000 comment_1: STEP-TIME=0.2 SEC ! linenum: 7.000 targname: HD48915 config: HRS opmode: WSCAN aperture: 0.25 sp_element: G200M wavelength: 2088-2193 num_exp: 1 time_per_exp: 342S s_to_n: 200 fluxnum_1: 6 priority: 1 param_1: FP-SPLIT=STD, param_2: STEP-PATT=5, param_3: WAVE-STEP=36 ! linenum: 7.500 targname: HD48915 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 27.4S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, param_4: MAP=END-POINT req_1: ONBOARD ACQ FOR 7.6; comment_1: STEP-TIME=0.2 SEC ! linenum: 7.600 targname: HD48915 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 20.4S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 8.000 comment_1: STEP-TIME=0.2 SEC ! linenum: 8.000 targname: HD48915 config: HRS opmode: WSCAN aperture: 0.25 sp_element: G270M wavelength: 2191-2683 num_exp: 1 time_per_exp: 578S s_to_n: 200 fluxnum_1: 7 fluxnum_2: 8 fluxnum_3: 9 fluxnum_4: 10 priority: 1 param_1: FP-SPLIT=STD, param_2: STEP-PATT=11, param_3: WAVE-STEP=41 ! ! end of exposure logsheet ! No scan data records found