9855( 3) - 05/05/03 10:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9855 Version: 3 Check-in Date: 05-May-2003 10:45:39 1.Proposal Title: Exploring Interstellar Krypton Abundance Variations at Kiloparsec Scales ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dr. Stefan I. B. Cartledge Louisiana State University & Agricultural & Medical College CoI: Prof. Geoffrey C. Clayton Louisiana State University & Agricultural N & Medical College CoI: Prof. James T. Lauroesch Northwestern University N CoI: Prof. David M. Meyer Northwestern University N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain high-resolution STIS echelle observations of the interstellar Kr I 1236 absorption toward eight stars situated in the Galactic disk beyond the Carina/Sagittarius or Perseus Arms. The measurement of interstellar krypton abundances is a relatively simple way to investigate elemental abundance variations in the Galaxy, since its dominant form is neutral and it is undepleted in the ISM. Furthermore, the intrinsic strengths of krypton's UV resonance lines combined with its low relative abundance to hydrogen produce weak, unsaturated features in typical Galactic sight lines. Previous GHRS and STIS measurements have demonstrated that Kr/H abundance ratios within the local spiral arm, the Orion Spur, are remarkably uniform; however, anomalously high krypton abundances have been measured for the only two sight lines extending also through gas outside the Orion Spur. This program is designed to determine whether these sight lines are isolated cases of enrichment, or if they are representative of large scale krypton abundance variations outside the local arm. Since krypton is undepleted in the ISM, these observations will also be relevant to the study of total elemental abundance and depletion variations for a variety of elements with resonance lines between 1170 and 1372 Angstroms. ------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 2] Observations Description ------------------------ Spectral V E(B-V) d l b Exposure Target Type (mag) (mag) (kpc) (D) (D) Time (s) Orbits HD35215 B1V 9.40 0.34 2.5 176.46 -3.19 6200 3 HD40893 B0IV 8.99 0.36 3.5 180.09 4.34 8400 4 HD116852 O9III 8.47 0.21 4.8 304.88 -16.13 3600 2 HD152590 O7.5V 8.48 0.39 1.8 344.84 1.83 10000 4 HD165246 O8V 7.71 0.34 2.1 6.40 -1.56 4000 2 HD166716 B0II/III 8.00 0.34 2.7 14.85 1.39 5500 3 HD168076 O5V 8.21 0.80 1.9 16.94 0.84 8400 4 HD168080 B0.5II 7.61 0.30 2.5 13.11 -1.27 4000 2 The goal of the proposed program is to obtain high resolution STIS echelle observations of interstellar Kr I 1236 angstrom absorption in the above sight lines. In addition, the Lyman-alpha neutral hydrogen line at 1215 angstroms will be measured and total hydrogen column densities derived with the aid of extant public FUSE data. Furthermore, the E140H setup centered at 1271 angstroms includes the Mg II 1240 angstrom doublet, which will function as a probe of unresolved saturation, and the O I 1356 angstom feature, which will aid in determining the influence of the heliocentric distance effect. With the exception of HD116852 and HD 152590, the target S/N for each spectrum is 50 at 1236 angstroms. At this sensitivity level, the 5 sigma detection threshold for Kr I 1236 is ~1.1 mA. This threshold is less than half the size of the smallest krypton feature measured by Cartledge (2002, PhD Thesis, NWU); hydrogen column density estimates for these sight lines indicate that Kr/H ratios within the range log_10(Kr/H) about -9.6 to -8.4 will be measurable, widely bracketing values that have been observed to date. For each of the new targets, SNAPSHOT observations of stars with similar spectral classes and E(B-V) values were uploaded to ftp.stsci.edu and input to the STIS Exposure Time Calculator renormalized to the 1180 angstrom fluxes in the existing FUSE spectra; the 0.2"x0.2" aperture and average background levels were used for each calculation. No violations of MAMA bright object count rate limits were reported by the Calculator. Exposure times were converted into an orbit request allowing for all necessary acquisition and exposure overheads specified in Chapter 6 of the HST Primer, with special reference to Table 6.15; a check against the prescription of Chapter 9 confirms the orbit calculations. For the targets HD116852 and HD152590, the exposure time of the previous SNAP8241 observations was increased by a factor of 9, in order to reduce the statistical uncertainty by a factor of 3. Duplications: HD116852 and HD152590.-- These targets were previously observed as part of SNAP8241, but that program was not specifically designed to measure the krypton abundance. Consequently, the uncertainties associated with these data points reduce the significance of the Kr/H ratios to ~1.5 sigma; even considering the two as a single measurement of the krypton abundance external to the Orion Spur, the gap is only relevant at a level of about 3 sigma. The importance of identifying the nature of this gap, however, requires that the measurement be significantly refined. Thus, we propose to re-observe both targets with exposure times sufficient to reduce the statistical errors by a factor of 3, improving the relevance of the gap between these Kr/H measurements and the ISM mean to at least 4 sigma in each case. In addition, the previous observation of HD116852 was sufficient only to distinguish a feature corresponding to a blend of 3 cloud components. However, Sembach & Savage (1994, ApJ 431 p. 201; 1996, ApJ 457, p211) identify 8 components in high S/N near-UV GHRS observations. The improved statistics resulting from re-observation of HD116852 will be sufficient to resolve additional components of oxygen absorption to serve as a reference for comparison of other elemental abundances in gas associated with the 9855( 3) - 05/05/03 10:47 - [ 3] Crux/Scutum, and perhaps also the Norma, Arm. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD035215 STAR, B0-B2 V-IV RA=05H24M28.34S +/- 0.1", J2000 V = 9.43+/-0.03 DEC=+30D11'31.03" +/- 0.2", TYPE=B1V PLATE-ID=00DH E(B-V) = 0.35 B-V = 0.09 Coordinate Source: GUIDE_STAR_CATALOG Comments: Magnitudes are from the Tycho Main Catalogue, coordinates are from the Guide Star Catalogue. Exposure time calculations using the on-line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.0 0.0 0.0 0.0 2 HD040893 STAR, B0-B2 V-IV RA=06H03M6.42S +/- 0.1", J2000 V = 8.99+/-0.02 DEC=+31D03'8.2" +/- 0.2" TYPE=B0IV E(B-V) = 0.37 B-V = 0.07 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 3 HD116852 STAR, GIANT O RA=13H30M23.5S +/- 0.1", DEC=- J2000 V = 8.48+/-0.02 78D51'20.5" +/- 0.2" TYPE=O9III E(B-V) = 0.17 B-V = -0.14 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 9855( 3) - 05/05/03 10:47 - [ 5] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 4 HD152590 STAR, MAIN SEQUENCE O RA=16H56M5.22S +/- 0.1", DEC=- J2000 V = 8.49+/-0.02 40D20'57.6" +/- 0.2" TYPE=O7.5V E(B-V) = 0.40 B-V = 0.09 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 5 HD165246 STAR, MAIN SEQUENCE O RA=18H06M4.68S +/- 0.1", DEC=- J2000 V = 7.77+/-0.02 24D11'43.9" +/- 0.2" TYPE=O8V E(B-V) = 0.40 B-V = 0.09 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 6 HD166716 STAR, B0-B2 III-I RA=18H12M28.5S +/- 0.1", DEC=- J2000 V = 8.14+/-0.02 15D22'23.7" +/- 0.2" TYPE=B0II/III E(B-V) = 0.37 B-V = 0.09 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 9855( 3) - 05/05/03 10:47 - [ 6] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 7 HD168076 STAR, MAIN SEQUENCE O, RA=18H18M36.41S +/- 0.1", DEC=- J2000 V = 8.24+/-0.03 EMISSION LINE STAR 13D48'2.4" +/- 0.2" TYPE=O5V E(B-V) = 0.75 B-V = 0.43 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 8 HD168080 STAR, B0-B2 III-I RA=18H18M46.89S +/- 0.1", DEC=- J2000 V = 7.61+/-0.02 18D10'19.8" +/- 0.2" TYPE=B0.5II E(B-V) = 0.32 B-V = 0.07 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates and magnitudes are from the Tycho Main Catalogue. Exposure time calculations using the on- line ETC and archival IUE or FUSE fluxes for the E140H grating centered at 1271 Angstroms yield a count rate well below the MAMA bright object safety limits. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.0 0.0 0.0 9855( 3) - 05/05/03 10:47 - [ 7] Visit: 01 Visit Priority: Visit Requirements: PCS MODE FINE SCHED 30% 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD035215 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 1.5 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HD035215 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1080 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD035215 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 4 1317 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 8] Visit: 02 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD040893 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 1 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HD040893 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1081 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD040893 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 6 1317 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 9] Visit: 03 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD116852 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 1.7 S CD III ------------------------------------------------------------------------------------------------------------------------------------ 2 HD116852 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1261 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD116852 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1600 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 10] Visit: 04 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD152590 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 1 S CD III ------------------------------------------------------------------------------------------------------------------------------------ 2 HD152590 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1120 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD152590 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 6 1346 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 11] Visit: 05 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD165246 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.3 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HD165246 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1079 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD165246 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1313 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 12] Visit: 06 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD166716 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.5 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HD166716 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1078 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD166716 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 4 1313 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 13] Visit: 07 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD168076 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.5 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HD168076 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1078 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD168076 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 6 1313 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 14] Visit: 08 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD168080 STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.3 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HD168080 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1079 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 3 HD168080 STIS/F ACCUM 0.2X0.2 E140H 1271 BINAXIS2=DEF,BINAXIS1=DEF 2 1313 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9855( 3) - 05/05/03 10:47 - [ 15] Summary Form for Proposal 9855 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND3 0.2X0.2 F28X50OIII ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT BINAXIS1=DEF BINAXIS2=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE SCHED 30% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140H ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD035215 HD040893 HD116852 HD152590 HD165246 HD166716 HD168076 HD168080 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1271 ------------------------------------------------------------------------------------------------------------------------------------