5895( 9) - 07/18/95 13:27 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5895 Version: 9 Check-in Date: ********** 1.Proposal Title: The Cool Atomic and Molecular Medium: Spectroscopy of the B5 Molecular Cloud Halo ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Peter Wannier Jet Propulsion Laboratory CoI: B-G Andersson Jet Propulsion Laboratory, Caltech N CoI: Steve Federman University of Toledo N CoI: David Lambert University of Texas N CoI: Jason Cardelli University of Wisconsin N ------------------------------------------------------------------------------------ 6. Abstract The cool atomic and molecular medium (CAMM) plays a pivotal role in the evolution of the ISM, shielding dense clouds from ionizing radiation and providing formation sites for simple molecules. Yet, observations of this component have been hampered by observational difficulties. For optical and UV absorption line studies, the problem is one of sampling: lines of sight to the brightest stars often miss the CAMM, usually found near dense, obscuring clouds. The present proposal uses the GHRS to target three stars near B5, a quiescent molecular cloud lying well below the Galactic Plane. We have carried out a program of supporting observations of B5, including full maps of radio wavelength CO and HI, and absorption line studies at HI (21 cm) and at optical wavelengths (CH, CH+ and CaII). Even in the quiescent B5, velocity offsets between the lines of different molecular and atomic species suggest that the atomic medium participates in (or is a result of?) active flows. The GHRS will provide the spectral resolution necessary to resolve the kinematics, along with the sensitivity required to target stars lying near B5. Wavelength settings are for CI, CO and C2. Together these spectral lines will yield gas pressure and density and information needed to understand the cloud structure, kinematics and chemical processes. ------------------------------------------------------------------------------------ 5895( 9) - 07/18/95 13:27 - [ 2] Observations Description ------------------------ We have chosen 3 stars in B5 to study with the GHRS, representing a subset of those already observed by us at optical wavelengths. The stars are picked to lie at different distances from the boundary of the CO cloud, their displacements from cloud center given in units of the CO cloud size. The 3 stars sample material is from 2 to 8 times the CO cloud size, providing complete coverage of possible stratification in the halo. The visual extinctions for all 3 stars all lie between 0.8 and 1.0, so that the same choice of spectral lines has been used for each star. We have chosen to use three wavelength settings, centered at 1272, 1279 and 1344 Angstroms. A wide range of line strengths is crucial in order to construct curves of growth and from these settings we can obtain complete information from a minimum of separate exposures. For CI the lines span (in terms of log(f- lamda)) -0.307 to 2.09; for CI*: -1.08 to 1.97; for CI**: -2.87 to 2.02 and for CO -0.08 to 1.29. The 1272A wavelength interval has weak CI lines for all three fine structure levels, important for establishing curves of growth. These are the only low f-value lines easily accessible to ECH-A (for the lines at ~ 1613A ECH -A has less than half the sensitivity). The 1279A wavelength interval provides stronger CI lines (for all three states) and the weak 12CO[A- X] (10-0) line, to establish its abundance in the lower rotational levels. The 1344A wavelength interval has 12CO and 13CO[A-X] (7-0) bands, ten times stronger than 10-0 band, and providing an intermediate point on the CO curve of growth. In addition, this band contains the C2 (F-X) band, providing a measure of rotational excitation in regions of somewhat higher density (cf., Federman et al., 1994). The integration times have been calculated assuming use of the Large Science Aperture (FP-SPLIT=4), taking account of the measured stellar fluxes, of the sensitivity of ECH-A, and of the blaze function. We have chosen to use the LSA to take advantage of its larger throughput, accepting a slight degradation in resolution. The stellar fluxes (at 1365A) were taken from TD1 satellite observations. The proposed S/N is in column 4, calculated per diode (rather than per pixel) although we expect to use the full spectral information for stronger lines (and the brighter stars). We will use STEP-PATT=7, four pixels per diode. After a thorough review of the available spectral lines, we feel that the best information is available by choosing comparable total integration times for each star, rather than by aiming for a fixed S/N ratio and identical spectral coverage. For a fixed number of orbits, the improved information available from the weaker features in the brighter stars more than offsets the loss in S/N in the weaker objects. From the complete information set, we will be able not only to derive the required pressures and temperatures and abundances, but we will also have enough redundancy in the brightest two stars to provide internal checks on our analysis, especially in terms of assumed homogeneity of the CAMM. Real Time Justification ----------------------- None Calibration Justification ------------------------- None Additional Comments ------------------- ------------------------------------------------------------------------------------ 5895( 9) - 07/18/95 13:27 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5895( 9) - 07/18/95 13:27 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD22951 ISM, HI CLOUD, STAR, B0 RA = 03H 42M 22.56S +/- 0.01S, J2000 V = V = 5.00 B-V = -0.02 E(B-V) = 0.27 F- -B2 V-IV, DEC = 33D 57' 53.6" +/- 0.1" +19.6 CONT(1365) = 7.78 E-10 Comments: Updated target data from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 -0.0017 -0.019 0.0 2 HD23180 ISM, HI CLOUD, STAR, B0 RA = 03H 44M 19.06S +/- 0.01S, J2000 V = V = 3.78 B-V = +0.08 E(B-V) = 0.35 F- -B2 III-I, DEC = 32D 17' 16.6" +/- 0.1" +18.5 CONT(1365) = 7.83 E-10 Comments: Updated target data from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0006 -0.009 0.0 3 HD23625 ISM, HI CLOUD, STAR, B0 RA = 03H 47M 52.61S +/- 0.02S, J2000 V = V = 6.90 B-V = +0.08 E(B-V) = 0.31 F- -B2 V-IV DEC = 33D 35' 59.6" +/- 0.2" +20.0 CONT(1365) = 7.60 E-11 Comments: Updated target data from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0003 -0.012 0.0 5895( 9) - 07/18/95 13:27 - [ 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 HD22951 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 11-13 SEARCH-SIZE=3 Comments: CENTER IN LSA, BRIGHTEST STAR IN FIELD TIME- STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 11 HD22951 HRS ACCUM 2.0 ECH-A 1272.13 FP-SPLIT=STD, 1 437.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 12 HD22951 HRS ACCUM 2.0 ECH-A 1279.17 FP-SPLIT=STD, 1 437.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 13 HD22951 HRS ACCUM 2.0 ECH-A 1344.69 FP-SPLIT=STD, 1 219S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5895( 9) - 07/18/95 13:27 - [ 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 HD23180 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 21-23 SEARCH-SIZE=3 Comments: CENTER IN LSA, BRIGHTEST STAR IN FIELD TIME- STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 21 HD23180 HRS ACCUM 2.0 ECH-A 1272.13 FP-SPLIT=STD, 1 437.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 22 HD23180 HRS ACCUM 2.0 ECH-A 1279.17 FP-SPLIT=STD, 1 437.4S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 23 HD23180 HRS ACCUM 2.0 ECH-A 1344.69 FP-SPLIT=STD, 1 219S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5895( 9) - 07/18/95 13:27 - [ 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 HD23625 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 31-33 SEARCH-SIZE=3 Comments: CENTER IN LSA, BRIGHTEST STAR IN FIELD TIME- STEP=0.2S ------------------------------------------------------------------------------------------------------------------------------------ 31 HD23625 HRS ACCUM 2.0 ECH-A 1272.13 FP-SPLIT=STD, 2 654S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 32 HD23625 HRS ACCUM 2.0 ECH-A 1279.17 FP-SPLIT=STD, 2 762S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 33 HD23625 HRS ACCUM 2.0 ECH-A 1344.69 FP-SPLIT=STD, 1 1089.6S STEP-PATT=7, COMB=FOUR, DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5895( 9) - 07/18/95 13:27 - [ 8] Summary Form for Proposal 5895 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 DOPPLER=DEF COMB=FOUR STEP-PATT=7 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 11-13 ONBOARD ACQ FOR 21-23 ONBOARD ACQ FOR 31-33 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 ECH-A ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD22951 HD23180 HD23625 ------------------------------------------------------------------------------------------------------------------------------------