5877( 8) - 11/30/95 16:32 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5877 Version: 8 Check-in Date: ********** 1.Proposal Title: The ^11B/^10B Ratio in the Interstellar Medium ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Steven Federman University of Toledo CoI: David Lambert University of Texas N CoI: Yaron Sheffer University of Texas N CoI: Jason Cardelli Villanova University N ------------------------------------------------------------------------------------ 6. Abstract We propose to measure the local interstellar ^11B/^10B ratio with the GHRS. These observations will provide the first measurements of the boron isotopic ratio beyond the solar system. The solar system ratio requires a source that enhances the ^11B/^10B ratio over that expected from spallation. Additional spallation via low energy galactic cosmic rays, whose flux is not directly measurable, may be the source. We will determine this flux from our data, and we will study the consequences of the derived flux on interstellar chemical processes and thermodynamics. Since production of ^11B is also possible in supernovae, our flux will be an upper limit. ------------------------------------------------------------------------------------ 5877( 8) - 11/30/95 16:32 - [ 2] Observations Description ------------------------ The targets were selected on the basis of the amount of neutral gas along the line of sight and of the simplicity of the absorption profile (in terms of velocity components) seen in high-resolution ground-based observations of K I (Hobbs 1974 ApJ 191 381) and of Na D (Welty, Hobbs & Kulkarni 1994 ApJ 436 152). Neutral potassium and sodium are found in appreciable quantities only in neutral gas because their ionization potentials are less than hydrogen's. For our investigation, most of the neutral material must reside in a single velocity component. Furthermore, the column density of hydrogen must be similar to that in the main component (v_helio = -15 km s^-1) toward Zeta Oph [N(H) = 1.32 * 10^21 cm^-2 (Savage, Cardelli & Sofia 1992 ApJ 401 706)]. The constraint derives from our detection of B II LAMBDA 1362 with an equivalent width of 1.78 +/- 0.29 mAngstrom in this velocity component (Federman et al. 1993). The design of our experiment revolves around our detection of B II toward Zeta Oph (Federman et al. 1993). Although not fully resolved even in the echelle mode, ECH-A can produce spectra revealing a broadened line with an asymmetry caused by the presence of the two isotopes. Synthetic spectra, based on our Zeta Oph results with G160M, clearly show absorption from both isotopes when ECH-A is utilized. A signal-to-noise ratio of 500 is required for our observations. Lower signal-to-noise ratios will mask the presence of any broadening and asymmetry. The synthesis was based on a shift of 13.3 mAngstrom (Joensson et al. 1994) and an isotopic ratio, ^11B/^10B = 4:1. We are also observing interstellar Ga II LAMBDA 1414 as a guide to the complexity of the component structure for our sight lines beyond what is possible from K I and Na D. Of particular note is that the B II and Ga II lines have similar strengths. Like boron, gallium is predominantly singly ionized; these two elements have similar reference (solar) abundances and they have similar depletions in the main component toward Zeta Oph. Absorption from Ga II based on ECH-A data only appears in this component (Cardelli, Ebbets & Savage 1991 ApJ 383 L23). Moreover, the oscillator strengths for B II LAMBDA 1362 and Ga II LAMBDA 1414 are similar. Cardelli et al. (1991) clearly detected the Ga II line from spectra with a signal-to-noise ratio of ~ 100. We based our exposure times on a S/N of 500 so that the Ga II line can be used as a template for component structure and instrumental profile in our analysis of B II LAMBDA 1362. Gallium has 2 isotopes as well as hyperfine components; we expect insignificant wavelength shifts and any resulting changes to the line profile from their presence. Of all the known interstellar lines, gallium absorption is the most similar to boron's, and even with some uncertainty arising from the presence of Ga isotopes and hyperfine structure, the Ga II line is the best template for our analysis. The exposure times were derived in the following way. Each of our stars was observed with OAO-2 and their fluxes were presented by Code & Meade (1979 ApJS 39 195). The fluxes at LAMBDA LAMBDA 1362, 1414 were derived from interpolation and were multiplied by the sensitivity of ECH-A in orders 41 and 40, respectively, taking into consideration the blaze function, the efficiency using STEP- PATT=7 (4 samples per diode), and the loss in sensitivity when using the Small Science Aperture (SSA). (The SSA is required for the highest possible resolution afforded by the GHRS.) For signal-to-noise ratios of 500 per pixel, the total exposure times were obtained for the B and Ga observations by multiplying the exposure time per diode by 4 for FP-SPLIT=4. The calculations also included the effects of scattered light. In deriving the number of orbits per target, we assumed BRIGHT=RETURN would be used with mirror N1 for a total acquisition time of 37^m per star. For this initial survey, we will observe three stars. Real Time Justification ----------------------- None. Calibration Justification ------------------------- None. Additional Comments ------------------- Should the need arise for more detailed descriptions of the line profile, we will obtain ultra-high-resolution spectra (LAMBDA/DELTA LAMBDA ~ 600,000) on K I LAMBDA 7699 from McDonald Observatory. ------------------------------------------------------------------------------------ 5877( 8) - 11/30/95 16:32 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5877( 8) - 11/30/95 16:32 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD38771 ISM, HI CLOUD, STAR, B0 RA = 05H 47M 45.38S +/- 0.01S, J2000 V = V = 2.07 B-V = -0.17 E(B-V) = 0.07 F- -B2 III-I, DEC = -09D 40' 10.8" +/- 0.1" +21.0 CONT(1362) = 1.78 E-8 F-CONT(1414) = 1.42 E-8 Comments: THIS IS A BRIGHT STAR. Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0002 -0.005 0.015 2 HD143275 ISM, HI CLOUD, STAR, B0 RA = 16H 00M 20.01S +/- 0.01S, J2000 V = -7.0 V = 2.28 B-V = -0.12 E(B-V) = 0.16 F- -B2 V-IV, DEC = -22D 37' 18.0" +/- 0.1" CONT(1362) = 1.47 E-8 F-CONT(1414) = 1.21 E-8 Comments: THIS IS A BRIGHT STAR. Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0007 -0.025 0.0 3 HD149757 ISM, HI CLOUD, RA = 16H 37M 9.54S +/- 0.01S, J2000 V = - V = 2.58 B-V = +0.02 E(B-V) = 0.32 F- MOLECULAR CLOUD, STAR, DEC = -10D 34' 1.6" +/- 0.1" 15.0 CONT(1362) = 4.58 E-9 F-CONT(1414) = MAIN SEQUENCE O, 4.29 E-9 Comments: THIS IS A BRIGHT STAR. Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0008 -0.023 0.003 5877( 8) - 11/30/95 16:32 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD38771 HRS ACQ 2.0 MIRROR-A1 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 11 SEARCH-SIZE=3 Comments: CENTER IN LSA, BRIGHTEST STAR IN FIELD TIME- STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 11 HD38771 HRS ACQ/PEA 0.25 MIRROR-A1 SEARCH-SIZE=5 1 5S ONBOARD ACQ FOR 12 KUP Comments: TIME-STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 12 HD38771 HRS ACQ/PEA 0.25 MIRROR-A1 SEARCH-SIZE=5 1 5S ONBOARD ACQ FOR 13-16 KUP Comments: TIME-STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 13 HD38771 HRS ACCUM 0.25 ECH-A 1360.5 FP-SPLIT=STD, 1 435.2S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 14 HD38771 HRS ACCUM 0.25 ECH-A 1361.0 FP-SPLIT=STD, 2 326.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 15 HD38771 HRS ACCUM 0.25 ECH-A 1412.7 FP-SPLIT=STD, 2 326.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 16 HD38771 HRS ACCUM 0.25 ECH-A 1413.3 FP-SPLIT=STD, 2 326.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5877( 8) - 11/30/95 16:32 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 20 HD143275 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 21 SEARCH-SIZE=3, LOCATE=EXTENDED Comments: CENTER IN LSA, BRIGHTEST STAR IN FIELD TIME- STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 21 HD143275 HRS ACQ/PEA 0.25 MIRROR-N1 SEARCH-SIZE=5 1 7.5S ONBOARD ACQ FOR 22-25 KUP Comments: TIME-STEP=0.3S ------------------------------------------------------------------------------------------------------------------------------------ 22 HD143275 HRS ACCUM 0.25 ECH-A 1360.5 FP-SPLIT=STD, 2 330S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 23 HD143275 HRS ACCUM 0.25 ECH-A 1361.0 FP-SPLIT=STD, 2 330S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 24 HD143275 HRS ACCUM 0.25 ECH-A 1412.5 FP-SPLIT=STD, 2 435.6S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 25 HD143275 HRS ACCUM 0.25 ECH-A 1413.0 FP-SPLIT=STD, 2 330S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5877( 8) - 11/30/95 16:32 - [ 7] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 30 HD149757 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 31 SEARCH-SIZE=3 Comments: CENTER IN LSA, BRIGHTEST STAR IN FIELD TIME- STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 31 HD149757 HRS ACQ/PEA 0.25 MIRROR-N1 SEARCH-SIZE=5 1 7.5S ONBOARD ACQ FOR 32-37 KUP Comments: TIME-STEP=0.3S ------------------------------------------------------------------------------------------------------------------------------------ 32 HD149757 HRS ACCUM 0.25 ECH-A 1360.5 FP-SPLIT=STD, 2 763.2S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 33 HD149757 HRS ACCUM 0.25 ECH-A 1360.9 FP-SPLIT=STD, 2 763.2S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 34 HD149757 HRS ACCUM 0.25 ECH-A 1361.3 FP-SPLIT=STD, 2 763.2S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 35 HD149757 HRS ACCUM 0.25 ECH-A 1412.5 FP-SPLIT=STD, 1 1089.6S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 36 HD149757 HRS ACCUM 0.25 ECH-A 1412.9 FP-SPLIT=STD, 1 1089.6S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 37 HD149757 HRS ACCUM 0.25 ECH-A 1413.3 FP-SPLIT=STD, 1 1198.2S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5877( 8) - 11/30/95 16:32 - [ 8] Summary Form for Proposal 5877 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 SEARCH-SIZE=5 DOPPLER=DEF COMB=FOUR STEP-PATT=7 FP-SPLIT=STD LOCATE=EXTENDED ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 11 ONBOARD ACQ FOR 12 ONBOARD ACQ FOR 13-16 ONBOARD ACQ FOR 21 ONBOARD ACQ FOR 22-25 ONBOARD ACQ FOR 31 ONBOARD ACQ FOR 32-37 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-A1 ECH-A MIRROR-N1 ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD38771 HD143275 HD149757 ------------------------------------------------------------------------------------------------------------------------------------