9383( 4) - 06/19/02 14:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9383 Version: 4 Check-in Date: 19-Jun-2002 14:45:39 1.Proposal Title: Probing the Grains Responsible for Extinction Using Small Magellanic Cloud Sightlines ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Karl Gordon University of Arizona CoI: Dr. Ulysses Sofia Whitman College N CoI: Dr. Geoffrey Clayton Louisiana State University N CoI: Dr. Karl Misselt Goddard Space Flight Center/NASA N CoI: Dr. Michael Wolff Space Science Institute N ------------------------------------------------------------------------------------ 5. Abstract Small Magellanic Cloud sightlines have the greatest potential to relate specific interstellar extinction features to distinct grain properties. The reasons for this are 1) prominent extinction features such as the 2175 Angstrom bump and the far- ultraviolet rise vary among SMC targets and 2) grain types may be very different from those in the Galaxy. Specifically, Welty et al. (2001) recently identified an SMC sightline that contains dust, but no silicate grains. Silicates are a dominant source of extinction in all dust models; the SMC may be the only location where the importance of silicates can be verified or disproven. We propose to explore the relationship between grain types and extinction toward 2 SMC stars with very different extinction curves; AzV 18 lacks a 2175 Angstrom bump and has a strong far- UV rise while the extinction curve towards the SMC star AzV 456 has a prominent 2175 Angstrom bump and a much weaker far-UV rise. We will compare the interstellar abundances of atoms that are prevalent in silicates (Si, Mg, Fe) toward these 2 stars and use the results to constrain dust extinction models. These SMC observations, which can only be obtained with STIS, are the only direct way to probe the connection between grain types/environments and extinction. The results from this study will be useful for modeling and understanding all regions that contain dust (AGN, circumstellar disks, star formation regions, etc.). ------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 2] Observations Description ------------------------ We are proposing to observe two stars in the Small Magellanic Cloud with the echelle gratings of STIS. To accomplish the goals of this proposal, we need observations with one E140H grating setting and two E230H grating settings. We used the online STIS exposure time calculator to calculate the exposure times to achieve a signal-to-noise ratio of 15 for all the lines we will measure. The observed spectra of AzV 18 and 456 (Gordon & Clayton 1998) were used to determine the fluxes at each of the grating settings. The exposure times need for AzV 18 are 22.7 hours for E140H(1234), 8.0 hours for E230H(1913), and 3.0 hours for E230H(2163). The exposure times need for AzV 456 are 10.0 hours for E140H(1234), 12.8 hours for E230H(1913), and 8.3 hours for E230H(2163). Due to the long exposures required for this program, we are requesting continuous viewing zone (CVZ) orbits. The number of orbits required was calculated by limiting each visit to 5 or fewer CVZ orbits and accounting for instrument overheads. We will do both a normal STIS acquisition and a STIS peakup acquisition at the beginning of every visit. The resulting number of CVZ orbits for AzV 18 is 15 (3 visits) for the E140H(1234) setting, 8 (2 visits) for the E230H(1913) and E230H(2163) settings. The resulting number of CVZ orbits for AzV 456 is 7 (2 visits) for the E140H(1234) setting, 14 (3 visits) for the E230H(1913) and E230H(2163) settings. The resulting total number of CVZ orbits requested is 44. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 AZV18 EXT-STAR, B0-B2 III-I RA=00H 47M 12.18S +/- 0.3", DEC= J2000 F(1600)=1.3+/-0.2e-13 -73D 6' 32.6" +/- 0.3", PLATE- V = 12.44+/-0.01 ID=06B1 Coordinate Source: GSC_SURVEY_PLATE 2 AZV456 EXT-STAR, B0-B2 III-I RA=01H 10M 55.77S +/- 0.3", DEC= J2000 F(1600)=1.3+/-0.2e-13 -72D 42' 55.88" +/- 0.3", PLATE- V = 12.89+/-0.02 ID=06B1 Coordinate Source: GSC_SURVEY_PLATE 9383( 4) - 06/19/02 14:47 - [ 4] Visit: 01 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV18 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 5] Visit: 02 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV18 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 6] Visit: 03 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV18 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV18 STIS/F ACCUM 0.2X0.0 E140H 1234 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 7] Visit: 04 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV18 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV18 STIS/N ACCUM 0.2X0.0 E230H 1913 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV18 STIS/N ACCUM 0.2X0.0 E230H 1913 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV18 STIS/N ACCUM 0.2X0.0 E230H 1913 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV18 STIS/N ACCUM 0.2X0.0 E230H 1913 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 8] Visit: 05 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV18 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV18 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV18 STIS/N ACCUM 0.2X0.0 E230H 1913 1 3840 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV18 STIS/N ACCUM 0.2X0.0 E230H 2163 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 9] Visit: 06 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV456 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV456 STIS/F ACCUM 0.2X0.0 E140H 1234 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV456 STIS/F ACCUM 0.2X0.0 E140H 1234 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV456 STIS/F ACCUM 0.2X0.0 E140H 1234 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV456 STIS/F ACCUM 0.2X0.0 E140H 1234 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 10] Visit: 07 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV456 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV456 STIS/F ACCUM 0.2X0.0 E140H 1234 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV456 STIS/F ACCUM 0.2X0.0 E140H 1234 2 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 11] Visit: 08 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV456 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 12] Visit: 09 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV456 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV456 STIS/N ACCUM 0.2X0.0 E230H 1913 2 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 13] Visit: 10 Visit Priority: Visit Requirements: VISIBILITY INTERVAL 85 M 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 AZV456 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.2 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 30 AZV456 STIS/N ACCUM 0.2X0.0 E230H 2163 1 3390 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 40 AZV456 STIS/N ACCUM 0.2X0.0 E230H 2163 3 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 AZV456 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.2 S CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 50 AZV456 STIS/N ACCUM 0.2X0.0 E230H 2163 1 1500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 60 AZV456 STIS/N ACCUM 0.2X0.0 E230H 2163 4 2340 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 9383( 4) - 06/19/02 14:47 - [ 14] Summary Form for Proposal 9383 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 0.2X0.09 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements VISIBILITY INTERVAL 85 M ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140H E230H ------------------------------------------------------------------------------------------------------------------------------------ Target Names AZV18 AZV456 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1234 1913 2163 ------------------------------------------------------------------------------------------------------------------------------------