! Proposal 5883, submission 1
! PI: Francis Keenan
! Received Mon Feb 13 09:43:25 EST 1995
! From: sembach@sundoggie.mit.edu
! Revised 6/28/95

Proposal_Information                         
              Title:  Properties of the High-Velocity Cloud
                      Towards HD 203664
  Proposal_Category:  GO
Scientific_Category:  Interstellar Medium
             Cycle:    5

Investigators
     PI_name:         Francis Keenan
     PI_Institution:  The Queen's University of Belfast

          CoI_Name:   Philip Dufton
   CoI_Institution:   The Queen's University of Belfast
           Contact:   N          

          CoI_Name:   Kenneth Sembach
   CoI_Institution:   Massachusetts Institute of Technology
           Contact:   Y          


Abstract:                        
    We will obtain high- and intermediate-resolution GHRS
    spectra of the +70 km/sec HVC seen toward HD 203664 in optical
    and radio spectra.  The observations will provide a unique
    opportunity to quantify the ionization structure of a HVC and
    accurately determine the chemical abundances of important
    elements such as C, N, O, Mg, Si, S, Cr, Mn, Fe, and Zn in
    high velocity interstellar material.  Our high spectral
    resolution optical data suggest that substructure may exist
    within the HVC which, if confirmed, would support the
    possibility that early-type stars at large distances from the
    Galactic plane are formed through star formation induced by
    collisions between cloudlets within HVCs.  We will test this
    hypothesis on the HD 203664 HVC with high S/N absorption line
    measurements made by the GHRS in its highest resolution mode.
    By combining a supporting set of optical and radio data with the 
    ultraviolet observations, we will study the velocity structure
    of the HVC, morphology, distance, and physical conditions of
    this HVC in greater detail than has been possible for any
    other high velocity cloud in the sky.

Questions                       

     Observing_Description:
    We will obtain spectroscopic observations of the HVC absorption toward 
    HD 203664 using both the highest resolution (echelle) and intermediate 
    resolution gratings of the GHRS.  The light of HD 203664 will be placed 
    in the large science aperture (LSA).  The data will be
    obtained with the default diode substepping (step-patterns 5 and 7). 
    Comb-addition and the FP-SPLIT=4 procedures will be used to reduce 
    fixed pattern noise in the data.  All exposures will be broken into 
    shorter exposures (either through the use of FP-SPLIT or through explicit 
    breaks) to ensure that geomagnetically-induced image blurring of the data 
    is minimized.
    Resolution and sensitivity estimates were taken from the post-COSTAR GHRS 
    instrument handbook (Version 5.0, May 1994).  Flux estimates for each 
    observation were determined from our recent IUE echelle spectra and should 
    be accurate to ~15%.  Exposure calculations include an allowance for 
    background determinations with the full diode array as part of the 
    substepping procedures.  The expected S/N values of ~50-70 are
    appropriate for a (Nyquist) sampling of 2 substeps/diode, but we will 
    obtain 4 samples per diode and rebin the data without loss of resolution 
    after acquisition.

   Real_Time_Justification:
    No special scheduling requirements are necessary.

Calibration_Justification:           
    No special scheduling requirements are necessary.  

      Additional_Comments:
    No additional comments at this time.

Fixed_Targets                           ! Section 5.1
  Target_Number:  1
    Target_Name:  HD203664
Alternate_Names:  BD+09D4793, GSC1110-01376
    Description:  STAR, B0-B2 V-IV
       Position:  RA=21H 23M 28.84S +/- 0.02S, 
                  DEC=+09D 55' 54.7" +/- 0.3"
        Equinox:  J2000
        RV_or_Z:  V = +110
          RA_PM:  +0.0003                     
         Dec_PM:  -0.014                      
          Epoch:  2000.000  
Annual_Parallax: 
           Flux:  V = 8.42 +/- 0.40,    
                  B-V = -0.19 +/- 0.10,
                  F-CONT(1240) = 4.0 +/- 0.2 E-11,
                  F-CONT(1550) = 0.8 +/- 0.2 E-11,
                  F-CONT(2600) = 1.1 +/- 0.2 E-11
       Comments:  Hipparcos coords and proper motions.


Visits   
!Visit Number 1                               
      Visit_Number:  1
Visit_Requirements:                     
  On_Hold_Comments:
    Visit_Comments:  First visit to obtain Side 1 spectra (4 orbits).
                     Number exposures beginning with 10.

!Line 1
     Exposure_Number: 10
         Target_Name: HD203664
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N1
          Wavelength:
 Optional_Parameters: BRIGHT=RETURN, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 20-70
            Comments: Expect about 74,000 cnt/s using mirror N1.
                      STEP-TIME = 0.2 seconds.  Ok as long as
                      BRIGHT=RETURN is used.

!Line 2
     Exposure_Number: 20
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-A
          Wavelength: 1335.1
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 1523.2S  !(S/N=50 @ 25.8M)
Special_Requirements: 
            Comments: Lines = C II, C II*

!Line 3
     Exposure_Number: 30
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-A
          Wavelength: 1303.4
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 1305.6S  !(S/N=50 @ 21.2M)
Special_Requirements:
            Comments: Lines = O I, O I*, Si II, S I

!Line 4
     Exposure_Number: 40
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G140M
          Wavelength: 1396.5
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=5, DOPPLER=ON
Number_of_Iterations: 1
!   Time_Per_Exposure: 979.2S !(S/N=50 @ 17.0M)
   Time_Per_Exposure: 1196.8S !(S/N=50 @ 17.0M)
Special_Requirements:
            Comments: Lines = Si IV, Ni II

!Line 5
     Exposure_Number: 50
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G140M
          Wavelength: 1248.3
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=5, DOPPLER=ON
Number_of_Iterations: 1
!   Time_Per_Exposure: 652.8S !(S/N=70 @ 10.6M)
   Time_Per_Exposure: 761.6S !(S/N=70 @ 10.6M)
Special_Requirements: 
            Comments: Lines = Ge II, N V, Mg II, S I, S II, Si II

!Line 6
     Exposure_Number: 60
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G140M
          Wavelength: 1544.5
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=5, DOPPLER=ON
Number_of_Iterations: 2
   Time_Per_Exposure: 1523.2S  !(S/N=50 @ 27.1M)
Special_Requirements:
            Comments: Lines = P II, C IV

!Line 7
     Exposure_Number: 70
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G140M
          Wavelength: 1199.0
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=5, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 1305.6S  !(S/N=50 @ 19.5M)
Special_Requirements:
            Comments: Lines = S III, Si II, Si III, Mn II, N I


!Visit Number 2
      Visit_Number:  2
Visit_Requirements:                     
  On_Hold_Comments:
    Visit_Comments:  Second visit to obtain Side 2 spectra (5 orbits).
                     Number exposures beginning with 110.

!Line 11
     Exposure_Number: 110
         Target_Name: HD203664
              Config: HRS
              Opmode: ACQ
            Aperture: 2.0
          Sp_Element: MIRROR-N2
          Wavelength:
 Optional_Parameters: BRIGHT=RETURN, SEARCH-SIZE=3
Number_of_Iterations: 1
   Time_Per_Exposure: 1.8S
Special_Requirements: ONBOARD ACQ FOR 120-210
            Comments: Expect about 400,000 cnt/s using mirror N2.
                      STEP-TIME = 0.2 seconds.  Ok as long as
                      BRIGHT=RETURN is used.

!Line 12
     Exposure_Number: 120
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2061.62
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 2
   Time_Per_Exposure: 761.6S  !(S/N=50 @ 24.6M)
Special_Requirements: 
            Comments: Lines = Cr II, Zn II

!Line 13
     Exposure_Number: 130
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 1807.6
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 2
   Time_Per_Exposure: 979.2S  !(S/N=50 @ 37.6M)
Special_Requirements:
            Comments: Lines = Si II, S I, Ni II

!Line 14
     Exposure_Number: 140
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2371.3
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 761.6S  !(S/N=50 @ 11.4M)
Special_Requirements:
            Comments: Lines = Fe II

!Line 15
     Exposure_Number: 150
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2603.3
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 1088.0S  !(S/N=50 @ 17.8M)
Special_Requirements:
            Comments: Lines = Fe II, Mn II

!Line 16
     Exposure_Number: 160
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2851.9
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 979.2S  !(S/N=50 @ 14.4M)
Special_Requirements:
            Comments: Lines = Mg I

!Line 17
     Exposure_Number: 170
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2800.0
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 761.6S  !(S/N=50 @ 11.0M)
Special_Requirements:
            Comments: Lines = Mg II

!Line 18
     Exposure_Number: 180
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2260.8
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
!   Time_Per_Exposure: 979.2S  !(S/N=50 @ 11.8M)
   Time_Per_Exposure: 1305.6S  !(S/N=50 @ 11.8M)
Special_Requirements:
            Comments: Lines = Fe II

!Line 19
     Exposure_Number: 190
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: ECH-B
          Wavelength: 2026.2
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=7, DOPPLER=ON
Number_of_Iterations: 1
   Time_Per_Exposure: 1414.4S  !(S/N=50 @ 23.7M)
Special_Requirements:
            Comments: Lines = Zn II, Mg I

!Line 20
     Exposure_Number: 200
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1856.5
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=5, DOPPLER=ON
Number_of_Iterations: 1
!   Time_Per_Exposure: 870.4S  !(S/N=50 @ 14.8M)
   Time_Per_Exposure: 979.2SS  !(S/N=50 @ 14.8M)
Special_Requirements:
            Comments: Lines = Al III

!Line 21
     Exposure_Number: 210
         Target_Name: HD203664
              Config: HRS
              Opmode: ACCUM
            Aperture: 2.0
          Sp_Element: G160M
          Wavelength: 1670.8
 Optional_Parameters: FP-SPLIT=FOUR, COMB=FOUR, STEP-PATT=5, DOPPLER=ON
Number_of_Iterations: 1
!   Time_Per_Exposure: 544.0S  !(S/N=50 @ 8.3M)
   Time_Per_Exposure: 652.8S  !(S/N=50 @ 8.3M)
Special_Requirements: 
            Comments: Lines = Al II


Data_Distribution                       

         Medium:        8MM             
Blocking_Factor:        10 

        Ship_To:        Kenneth Sembach
                        Center for Space Research
                        MIT 6-216
                        77 Massachusetts Avenue
                        Cambridge, MA  02139

       Ship_Via:        UPS            

Recipient_Email:        sembach@sundoggie.mit.edu