6617( 5) - 08/26/96 17:01 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6617 Version: 5 Check-in Date: 26-Aug-1996 16:58:44 1.Proposal Title: The ISM Toward Nearby High-Velocity Stars: Accurate H Columns, D/H, and H Walls ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle INTERSTELLAR MEDIUM GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Jeffrey Linsky University of Colorado CoI: Brian Wood JILA/University of Colorado N ------------------------------------------------------------------------------------ 6. Abstract Accurate measurements of the deuterium/hydrogen (D/H) ratio in local interstellar gas can provide a critical benchmark for estimates of the primordial D/H ratio, one of the major constraints on Big Bang cosmology, and credible measurements of spatial variations in D/H can constrain Galactic chemical evolution models. Our extensive modelling of H I and D I absorption in the Ly-alpha\ line toward nearby stars and comparison with GHRS echelle spectra has shown that the D I column density can be measured accurately, but that the H I column is uncertain because the opacity is high and the intrinsic stellar emission line is not well known. An elegant solution to this problem is to study the interstellar absorption for lines of sight to NEARBY HIGH-VELOCITY stars. Large stellar radial velocities shift half of the stellar emission line away from the interstellar absorption. One can then determine what H I column density produces an intrinsic stellar line profile centered on the stellar radial velocity. We propose to study 2 high radial velocity stars located within 6 pc to measure accurately: (1) the H I column densities, (2) the mean value and possible variations in D/H, (3) trace the size, temperature, density, and turbulent velocity of the local interstellar cloud (LIC) and the G cloud, and (4) search for hot H I that theoretical models predict should be located at the interfaces between the ISM and solar/stellar winds. GHRS spectra of Alpha Cen and Epsilon Indi provide the first evidence for this hot H I. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to observe the 2 stars listed in Table 1. Each observation will begin with an acquisition by the GHRS on Side 2. TABLE 1. GALACTIC COORDINATES AND UPWIND ANGLES OF TARGET STARS Target & Alt. Name &Dist.(pc)& l & b &Cloud& v_{ISM}&theta & theta_{\\odot} ------------------------------------------------ ------------------------------ HD 201091 & 61 Cyg A & 3.46 & 83&-6 & LIC & 85.0 & 45.7 & 79.0 HD 26965 & 40 Eri A & 4.83 &201&-37& LIC & 123.2 & 57.8 & 155.2 We will then obtain an ECH-B exposure through the SSA centered on the Mg II lines at 2800 Angstroms to obtain the velocity of the interstellar absorption and to determine whether there are multiple velocities in the line of sight. We will then switch to Side 1 and obtain a long exposure (2 orbits) with ECH-A through the SSA centered at 1215.5 Angstrom. Our exposures are scaled from the excellent exposure of Epsilon Indi using the integrated Ly-alpha\\ fluxes obtained from IUE spectra by Landsman & Simon (ApJ, 408, 305). Real Time Justification ----------------------- We have no special requirements. No coordinated observations are needed. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6617( 5) - 08/26/96 17:01 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD201091 STAR, K V-IV, ISM, HI RA = 21H 06M 53.94S +/- 0.1S, J2000 V = -64 V = 5.21+/-0.01 CLOUD DEC = +38D 44' 57.7" +/- 0.5" B-V = 1.18+/-0.01 E(B-V) = 0.00+/-0.01 TYPE=K5V F-LINE(1216)=5.4+/-0.5e-12 W-LINE(1216)=0.6+/-0.1 F-LINE(2795)=2.2+/-1.1e-11 W-LINE(2795)=0.6+/-0.1 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.3535 3.2026 0.289 2 HD26965 STAR, K V-IV, ISM, HI RA = 4H 15M 16.32S +/- 0.05S, J2000 V = -42 V = 4.43+/-0.01 CLOUD DEC = -7D 39' 9.9" +/- 0.5" B-V = 0.82+/-0.01 E(B-V) = 0.00+/-0.01 TYPE=K1V F-LINE(1216)=2.8+/-0.5e-12 W-LINE(1216)=0.6+/-0.1 F-LINE(2795)=1.2+/-0.6e-11 W-LINE(2795)=0.6+/-0.1 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.1497 -3.418 0.207 6617( 5) - 08/26/96 17:01 - [ 2] 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD201091 HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 2 Comments: STEP-TIME = 0.2 sec ------------------------------------------------------------------------------------------------------------------------------------ 2 HD201091 HRS ACQ/PEA 0.25 MIRROR-N2 1 5.0 S ONBOARD ACQ FOR 3-6 KUP Comments: STEP-TIME = 0.2 sec ------------------------------------------------------------------------------------------------------------------------------------ 3 WAVE HRS ACCUM SC2 ECH-B 2799 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 4 HD201091 HRS ACCUM 0.25 ECH-B 2799 FP-SPLIT=STD 1 979.2 S ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 ECH-A 1216 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 HD201091 HRS ACCUM 0.25 ECH-A 1216 FP-SPLIT=STD 3 1632.0 ------------------------------------------------------------------------------------------------------------------------------------ 6617( 5) - 08/26/96 17:01 - [ 3] 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 ------------------------------------------------------------------------------------------------------------------------------------ 7 HD26965 HRS ACQ 2.0 MIRROR-N2 1 1.8 S ONBOARD ACQ FOR 8 Comments: STEP-TIME = 0.2 sec ------------------------------------------------------------------------------------------------------------------------------------ 8 HD26965 HRS ACQ/PEA 0.25 MIRROR-N2 1 5.0 S ONBOARD ACQ FOR 9-12 KUP Comments: STEP-TIME = 0.2 sec ------------------------------------------------------------------------------------------------------------------------------------ 9 WAVE HRS ACCUM SC2 ECH-B 2799 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 10 HD26965 HRS ACCUM 0.25 ECH-B 2799 FP-SPLIT=STD 1 870.4 S ------------------------------------------------------------------------------------------------------------------------------------ 11 WAVE HRS ACCUM SC2 ECH-A 1216 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 12 HD26965 HRS ACCUM 0.25 ECH-A 1216 FP-SPLIT=STD 3 1632.0 ------------------------------------------------------------------------------------------------------------------------------------ 6617( 5) - 08/26/96 17:01 - [ 4] Summary Form for Proposal 6617 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3-6 ONBOARD ACQ FOR 8 ONBOARD ACQ FOR 9-12 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 ECH-B ECH-A ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD201091 WAVE HD26965 ------------------------------------------------------------------------------------------------------------------------------------