8145( 3) - 02/01/00 13:54 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8145 Version: 3 Check-in Date: 17-Feb-1999 11:14:23 1.Proposal Title: Abundances and Physical Conditions in the ISM of the Magellanic Clouds ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Daniel Welty University of Chicago CoI: Dr. J. Chris Blades Space Telescope Science Institute N CoI: Dr. Edward Fitzpatrick Villanova University N CoI: Dr. Lewis Hobbs University of Chicago N CoI: Dr. James Lauroesch Northwestern University N CoI: Dr. Donald York University of Chicago N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain high-resolution UV spectra of one star in the SMC, as part of a detailed study of the interstellar medium in and toward the Magellanic Clouds --- nearby systems of low metallicity and low dust-to-gas ratio for which stellar abundance data are also available. We will use the STIS echelle modes to obtain absorption-line profiles for species such as C I, Mg I, N I, O I, S II, Zn II, Mg II, Si II, Cr II, Mn II, Fe II, and Ni II. These UV spectra will be used, together with optical spectra of Na I, K I, and Ca II obtained at higher resolution and/or S/N ratio and with far-UV spectra obtained with FUSE, to determine accurate abundances, pressures, temperatures, densities, and radiation fields for both neutral and ionized clouds in the SMC and Galactic disk and halo. Determining detailed abundances/depletions (for many elements) and local physical conditions for diverse environments in our Galaxy and in the Magellanic Clouds will aid in understanding the absorption-line systems seen toward distant QSO's. ------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 2] Observations Description ------------------------ We will observe 1 SMC star with STIS using the E230H/NUV MAMA (two settings) and E140H/FUV MAMA (one setting), in each case with the 0.2X0.09 slit. High spectra resolution and a clean line spread function are very desirable, due to the complexity of the line of sight. plan to observe the 7 stars over a three- year period. The star selected has a higher N(H) (3.5e21 cm^-2) and E(B-V) (0.09 SMC plus 0.04 Galactic), and is located in a different region of the SMC (the wing) than Sk 108 (observed in Cycle 4 with GHRS) --- to gauge the uniformity of the relative abundances for different environments in the SMC. It is relatively bright, both in the optical (V = 12.5) and in the UV. For this late-O supergiant, there should be minimal confusion from stellar lines and circumstellar H II regions. The existing optical spectra show fairly distinct, multiple components (rather than broad, smooth, highly blended absorption) --- to facilitate analysis of individual components. We have selected grating tilts to cover (where possible) both strong and weak lines of multiple ionization stages of (roughly) a dozen elements (both depleted and undepleted). At the requested S/N ratio, simultaneous fits to the echelle profiles of lines of different strength (of the same or similarly distributed species) yield well- defined, consistent component structures and accurate abundances for a range in component N(H) (e.g., Fitzpatrick & Spitzer 1997; Welty et al. 1997). Si III, S III, and Si II* will provide information on H II regions; C I will give information on cold gas; C I/Zn II, Mg I/Mg II, and Na I/Zn II will constrain ionization balance. Grating Lambda_0 Range Species, E140H 1271 1170-1372 CI (many), CII, CII*, NI (3), NV (2), OI (2), MgII (2 weak), SiII (4), SiII*, SiIII, PII, SII (3), SIII, MnII (3 weak), NiII (2) E230H 2163 2024-2301 MgI, CrII (3), FeII(2 weak), ZnII (2) E230H 2713 2574-2851 MnII (3), Fe II (2 strong), Mg II (2 strong) We aim to achieve a S/N of about 40 per resolution element in the extracted echelle spectra (slightly better than obtained for our GHRS spectra of Sk 108, and comparable to GHRS spectra of several Galactic halo stars). The exposure estimates given below are for the UV fluxes from IUE low dispersion spectra. We have used the on-line (web-based) exposure calculator for these estimates. The total exposures given below will of necessity be split into roughly 40-50 min sub-exposures, due to the policy of obtaining regular wavecals. With acquisition, instrumental overhead, and an extra peakup inserted for visits longer than 4 orbits, the total time comes to roughly 20 orbits/4 visits. Grating/Setting/Range S/N Flux Exposure Orbits (hours) E140H 1271 1170- 1372 40 1.0e-12 5.9 5+5 E230H 2163 2024-2301 40 0.5e-12 4.0 5 E230H 2713 2574- 2851 40 0.3e-12 3.9 5 The target's UV flux is within a factor 2-3 of the star Sk -69 215 (used as an example for both exposure time estimates and acquisition strategy in the STIS handbook). From inspection of the guide star catalogue and the digitized sky survey plates (in conjunction with appropriate finding charts), it appears that the target is the brightest source within 5 arcsec of the nominal position. It thus should be sufficient to use a CCD point source acquisition, (at the minimum exposure time), and a peakup in dispersed light through the slit used for the spectral observations. The peakup times will be about xx min. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 3] Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SK155 EXT-STAR, Supergiant O RA=1H 14M 50.20S +/- 0.2S, DEC=- 2000 V = 12.5+/-0.1 73D 20' 17.2" +/- 0.8" B-V = -0.15+/-0.01 E(B-V) = 0.13+/-0.03 TYPE=O9I F(1270)=1.1+/-0.1e-12 F(1900)=0.6+/-0.1e-12 F(2100)=0.5+/-0.1e-12 F(2700)=0.3+/-0.1e-12 Comments: Coords from Hipparcos input catalogue 8145( 3) - 02/01/00 13:54 - [ 5] Visit: 01 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 ------------------------------------------------------------------------------------------------------------------------------------ 101 SK155 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 102 CD P ------------------------------------------------------------------------------------------------------------------------------------ 102 SK155 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 1 S ONBOARD ACQ FOR 103-104 CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 103 SK155 STIS/F ACCUM 0.2X0.0 E140H 1271 1 2305 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 104 SK155 STIS/F ACCUM 0.2X0.0 E140H 1271 3 3235 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 6] 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 ------------------------------------------------------------------------------------------------------------------------------------ 201 SK155 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 202 CD P ------------------------------------------------------------------------------------------------------------------------------------ 202 SK155 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 1 S ONBOARD ACQ FOR 203-204 CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 203 SK155 STIS/F ACCUM 0.2X0.0 E140H 1271 1 2305 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 204 SK155 STIS/F ACCUM 0.2X0.0 E140H 1271 3 3235 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 7] 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 ------------------------------------------------------------------------------------------------------------------------------------ 301 SK155 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 303-304 CD P ------------------------------------------------------------------------------------------------------------------------------------ 303 SK155 STIS/N ACCUM 0.2X0.2 E230H 2163 1 2720 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 304 SK155 STIS/N ACCUM 0.2X0.2 E230H 2163 6 1605 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 8] 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 ------------------------------------------------------------------------------------------------------------------------------------ 401 SK155 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 403-404 CD P ------------------------------------------------------------------------------------------------------------------------------------ 403 SK155 STIS/N ACCUM 0.2X0.2 E230H 2713 1 2720 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 404 SK155 STIS/N ACCUM 0.2X0.2 E230H 2713 6 1605 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 9] 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 ------------------------------------------------------------------------------------------------------------------------------------ 501 SK155 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 503-504 CD P ------------------------------------------------------------------------------------------------------------------------------------ 503 SK155 STIS/N ACCUM 0.2X0.2 E230H 1913 1 2720 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 504 SK155 STIS/N ACCUM 0.2X0.2 E230H 1913 3 3235 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8145( 3) - 02/01/00 13:54 - [ 10] Summary Form for Proposal 8145 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 0.2X0.09 0.2X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 102 ONBOARD ACQ FOR 103-104 ONBOARD ACQ FOR 202 ONBOARD ACQ FOR 203-204 ONBOARD ACQ FOR 303-304 ONBOARD ACQ FOR 403-404 ONBOARD ACQ FOR 503-504 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140H E230H ------------------------------------------------------------------------------------------------------------------------------------ Target Names SK155 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1271 2163 2713 1913 ------------------------------------------------------------------------------------------------------------------------------------