! File: 4573C.PROP ! Database: PEPDB ! Date: 22-FEB-1994:18:14:05 coverpage: title_1: BORON IN ORION: CYCLE 3 MEDIUM sci_cat: HOT STARS sci_subcat: CHEMICAL ABUNDANCES proposal_for: GO pi_fname: DOUGLAS pi_mi: R. pi_lname: GIES pi_inst: GEORGIA STATE UNIVERSITY pi_country: USA hours_pri: 4.50 num_pri: 3 hrs: Y funds_length: 12 off_fname: JOHM off_mi: M off_lname: BOREK off_title: VP FIN. AFFAIRS off_inst: GEORGIA STATE UNIVERSITY off_addr_1: UNIVERSITY PLAZA off_city: ATLANTA off_state: GA off_zip: 30303 off_country: USA off_phone: 404-651-2331 ! end of coverpage abstract: line_1: The abundance of Boron will be derived from the B II 1362A resonance line_2: line for a sample of massive (8-9 Msun) stars. line_3: Stars near the Trapezium in Orion are enriched in Oxygen. This enrichment is line_4: presumed to be due to enrichment of the parental molecular cloud with Oxygen line_5: from SNeII. If B is synthesized by neutrino-induced spallation in SNeII, the line_6: O-rich Orion stars will be overabundant in Boron. This prediction will be line_7: tested by measuring the 1362A line in the most O-rich Orion star, and line_8: by comparing the Boron abundance with that for other O-normal Orion stars. ! ! end of abstract general_form_proposers: lname: GIES fname: DOUGLAS title: PI mi: R. inst: GEORGIA STATE UNIVERSITY country: USA ! lname: LAMBERT fname: DAVID mi: L. inst: UNIVERSITY OF TEXAS country: USA ! lname: VENN fname: KIMBERLY inst: UNIVERSITY OF TEXAS country: USA ! lname: CUNHA fname: KATIA inst: UNIVERSITY OF TEXAS country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: INTRODUCTION. line_2: The abundance of boron in early type stars was discussed in the late 1970s line_3: using spectra at 1360A from the Copernicus satellite. The seminal paper is line_4: Boesgaard and Heacox (1978 ApJ 226 888 [BH]). To our knowledge no new line_5: information has been provided by the IUE satellite. We propose to return to B line_6: to investigate its synthesis. BH showed line_7: through synthetic spectra and analysis of Copernicus spectra that the B line_8: abundance was obtainable from the B II resonance (singlet) line in early-A to line_9: early-B stars. The B abundance from 16 normal stars having temperatures of 9000 line_10: to 25000K was independent of temperature and close to the meteoritic value. line_11: Above 25000K, the B II line is weak and blended with a much stronger Si III line_12: line. In short, BH's study shows that the 1362A line is a useful monitor of the line_13: stellar B abundance for B stars. line_14: We shall improve upon BH's study principally by acquiring spectra of higher line_15: S/N at a resolution comparable to that of Copernicus, and by using nearby line_16: Si III lines to better gauge the strength of the Si III line_17: blended with the B II. We expect also to be able to establish more securely the line_18: continuum level, and to provide more complete synthetic spectra. line_20: LOCAL ENRICHMENT OF THE ORION ASSOCIATION. line_21: Large molecular clouds may produce several successive stellar generations and line_22: possibly the first stars to die may pollute the portions of a cloud that later line_23: forms stars. The Orion OB association consists of 4 major pieces of different ! question: 2 section: 2 line_1: ages (Blaauw 1964 ARAA 2 213). Olive and Schramm (1982 ApJ 257 276) suggested line_2: that the younger subgroups could be enriched in products of SNeII from massive line_3: stars. Our search for this enrichment shows that the region of the Trapezium, line_4: the region now forming stars, is enriched in oxygen: our principal target line_5: HD36285's O abundance is about 60% higher than the well-defined abundance of line_6: the older stars (Cunha and Lambert 1992 ApJ 399 586). (HD36285's N abundance line_7: is not distinctive.) Since O is a principal product of SNeII from massive line_8: stars, we identify the enrichment with that hypothesized by Olive and Schramm. line_9: This identification offers a chance to test the proposal that B is line_10: synthesised in SNeII by neutrino-induced spallation (Woosley et al. 1990 ApJ line_11: 356 272): v + 12C --> 11B, in short, where the 12C is in the C-shell of the line_12: star. Calculations (Woosley 1991 "Supernovae", Springer-Verlag p.206) show that line_13: the O enrichment of HD36285 could be accompanied by a similar enrichment of B. line_14: We plan to observe the most O-rich star and 2 O-normal stars that bracket line_15: the temperature of the O-rich star in order to search for a B enrichment of the line_16: O-rich star. Detection of excess B would be the first direct evidence line_17: that 11B is made in SNeII. line_18: Production of 11B by SNeII would resolve a longstanding problem concerning line_19: the synthesis of 11B and 10B. Synthesis of the light elements is largely the line_20: responsibility of spallation reactions between the galactic cosmic rays and line_21: interstellar nuclei (e.g., p + O --> 10B etc.) These reactions predict 11B/10B line_22: = 2.5 but the meteoritic value (the only available measurement) is 11B/10B = line_23: 4.05. SNeII may have contributed the additional 11B. (Spallation can provide a ! question: 2 section: 3 line_1: higher isotopic ratio if low energy CRs are invoked.) ! question: 3 section: 1 line_1: The B II 1362A line will be observed with GHRS/G160M/SSA to a S/N of 400. line_2: The targets are local, visually bright B-type stars of luminosity classes V: line_3: Star Teff log g vsini Comment line_4: HD35039 20600 3.7 16 Orion member, normal N and O abundance line_5: HD35299 24000 4.3 5 Orion member, normal N and O abundance line_6: HD36285 22000 4.4 5 Orion member, O 60% above normal ! question: 4 section: 1 line_1: Boron is a trace element with no detectable transitions in the visible or line_2: infra-red spectra of hot stars. IUE, while providing about the same spectral line_3: resolution of G160M, lacks the capability to provide adequate S/N to measure line_4: the B II line accurately. Several of our stars have temperatures such that the line_5: B II line is weak and high S/N is needed to define it accurately. This is well line_6: shown by the synthetic spectra computed by Boesgaard and Heacox (1978 ApJ 226 line_7: 888) and by the fact that, after more than a decade, IUE has yet to provide a B line_8: abundance for a hot (or a cool) star. The desired S/N is achievable with GHRS, line_9: as we have demonstrated with our GTO observations of interstellar CO in Zeta line_10: Oph where S/N = 900 was achieved with a strategy of substepping and exposures line_11: at slightly different carrousel positions. line_13: Leckrone and Adelman (1989 ApJS 71 387) have given an extensive discussion of line_14: the S/N ratio of high-dispersion IUE spectra and the gains that result from co- line_15: addition of spectra. They show that "the average signal-to-noise ratio (S/N) at line_16: the continuum level in well exposed stellar spectra varies from 10 to 20" and line_17: "The co-addition procedure yields an improvement in S/N by factors ranging from line_18: 2.3 to 2.9". In other words, a S/N of about 50 may be achievable. A S/N >100 is line_19: certainly not possible. Boesgaard and Heacox's spectra have generally S/N of line_20: about 100. We need the more accurate spectra from HST/GHRS to search for what line_21: are possibly small star-to-star differences in the B abundance. line_23: Boron abundances for A and B-type stars were derived by Boesgaard and Heacox ! question: 4 section: 2 line_1: from their Copernicus spectra. Their sample is inadequate to meet our goals, line_2: e.g., no stars from Orion. line_4: Exposure times were calculated for GHRS/G160M/SSA using observed 1360A fluxes, line_5: as given by the TD-1 satellite (1976 ESA SR-27) or the IUE Spectral Atlas. A line_6: S/N = 400 was the target but some minor compromises were made. ! question: 5 section: 1 line_1: None. ! question: 6 section: 1 line_1: None. ! question: 7 section: 1 line_1: Spectra will be reduced in Atlanta. The PI with Dr D Lambert and Katia line_2: Cunha will analyse the Orion stars; chemical evolution of the Orion Association line_3: forms Cunha's Ph.D. dissertation. Calculations will be done with Kurucz model line_4: atmospheres. Synthetic spectra at 1360A have already been computed. All line_5: participants have extensive experience in model atmospheres/synthetic spectra line_6: analysis. ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: DLL is PI on all these GTO proposals and a Co-I on the GO proposals: line_2: GTO1064 Boron in Main Sequence Stars, not related line_3: GTO1065 Isotopic Abundances of Carbon and Oxygen and Fractionation of line_4: Interstellar Carbon Monoxide, not related line_5: GTO1066 Carbon Chemistry in Interstellar Diffuse Clouds, not related line_6: GTO1067 Old Novae and Cataclysmic Variables - DQ Her, not related line_7: GTO1068 Epsilon Aurigae- A Search for the Secondary, not related line_8: GO3824 A Search for Silicon and Carbon in GP Com, not related line_9: GO3479 Boron in Pop. II Dwarfs - Primeval or Spallated?, not related line_11: Note: GTO1064 and GO3479 refer to Boron and its chemical evolution over the line_12: lifetime of the Galaxy, and not to the problems of B in hot stars. line_14: First Results from the GHRS: C I, S I, and CO toward Xi Persei and the line_15: Physical Conditions of the Diffuse Clouds. A M Smith, F C Bruhweiler, line_16: D L Lambert, B D Savage, J A Cardelli, D C Ebbets, C-H Lyu, & Y Sheffer, line_17: ApJ, 377, L61, 1991. line_18: Fractionation of CO in the Diffuse Clouds toward Zeta Oph, Y Sheffer, line_19: S R Federman, D L Lambert, & J A Cardelli, ApJ, 397, 482, 1992. line_20: The Abundance of Boron in three Halo Stars, D K Duncan, D L Lambert, line_21: & M Lemke, ApJ, 401, 584, 1992. ! question: 10 section: 1 line_1: Adequate computing facilities are available at both participating institutions. line_2: Although the program stars have already be extensively analysed by us on the line_3: basis of their visual spectra, additional spectra, if required, can be readily line_4: obtained at the McDonald Observatory in west Texas. ! !end of general form text general_form_address: lname: GIES fname: DOUGLAS mi: R. category: PI inst: Georgia State University addr_1: DEPARTMENT OF PHYSICS AND ASTRONOMY addr_2: GEORGIA STATE UNIVERSITY city: ATLANTA state: GA zip: 30303 country: USA phone: 404-651-2932 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: HD35039 name_2: BD-00D930 descr_1: A,110 pos_1: RA = 5H 19M 12.47S +/- 0.02S, pos_2: DEC = -00D 25' 49.03" +/- 0.06" equinox: 1950 pm_or_par: N rv_or_z: V=28.2 fluxnum_1: 1 fluxval_1: V=4.73, TYPE=B2IV fluxnum_2: 1 fluxval_2: B-V=-0.17, E(B-V)=0.07 fluxnum_3: 2 fluxval_3: F(1360)=1.3E-9 ! targnum: 2 name_1: HD35299 name_2: BD-00D936 descr_1: A,110 pos_1: RA = 5H 21M 8.75S +/- 0.09S, pos_2: DEC = -00D 12' 18.70" +/- 0.09" equinox: 1950 pm_or_par: N rv_or_z: V=21.0 fluxnum_1: 1 fluxval_1: V=5.70, TYPE=B1.5V fluxnum_2: 1 fluxval_2: B-V=-0.21, E(B-V)=0.04 fluxnum_3: 2 fluxval_3: F(1360)=7.3E-10 ! targnum: 3 name_1: HD36285 name_2: BD-07D1099 descr_1: A,110 pos_1: RA = 5H 27M 55.63S +/- 0.15S, pos_2: DEC = -07D 28' 20.03" +/- 0.15" equinox: 1950 pm_or_par: N rv_or_z: V=11.3 fluxnum_1: 1 fluxval_1: V=6.33, TYPE=B2V fluxnum_2: 1 fluxval_2: B-V=-0.19, E(B-V)=0.05 fluxnum_3: 2 fluxval_3: F(1360)=3.0E-10 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: B2-ACQ targname: # config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 1.8S s_to_n: 100 fluxnum_1: 2 priority: # param_1: SEARCH-SIZE=3, param_2: BRIGHT=RETURN ! linenum: 2.000 sequence_1: DEFINE sequence_2: BORON2 targname: # config: HRS opmode: ACCUM aperture: 0.25 sp_element: G160M wavelength: 1362.0 num_exp: # time_per_exp: 10M s_to_n: 500 fluxnum_1: 1 priority: # param_1: FP-SPLIT=STD, param_2: STEP-PATT=5 ! linenum: 4.000 sequence_1: USE sequence_2: B2-ACQ targname: HD35039 time_per_exp: X1 priority: 1 req_1: ONBOARD ACQ FOR 5; CYCLE 3 / 4-5 ! linenum: 5.000 sequence_1: USE sequence_2: BORON2 targname: HD35039 num_exp: 2 time_per_exp: X1 priority: 1 req_1: CYCLE 3 ! linenum: 6.000 sequence_1: USE sequence_2: B2-ACQ targname: HD35299 time_per_exp: X1 priority: 1 req_1: ONBOARD ACQ FOR 7; CYCLE 3 / 6-7 ! linenum: 7.000 sequence_1: USE sequence_2: BORON2 targname: HD35299 num_exp: 3 time_per_exp: X1 priority: 1 req_1: CYCLE 3 ! linenum: 8.000 sequence_1: USE sequence_2: B2-ACQ targname: HD36285 time_per_exp: X1 priority: 1 req_1: ONBOARD ACQ FOR 9; CYCLE 3 / 8-9 ! linenum: 9.000 sequence_1: USE sequence_2: BORON2 targname: HD36285 num_exp: 8 time_per_exp: X1.1 priority: 1 req_1: CYCLE 3 ! ! end of exposure logsheet ! No scan data records found