!  File:  2282C.PROP
!  Database:  PEPDB
!  Date:  17-FEB-1994:04:40:21

coverpage:

  title_1:         SENSITIVE UV SPECTROSCOPY OF A HELIUM ATMOSPHERE DEGENERATE STAR
    sci_cat:       STELLAR ASTROPHYSICS
    sci_subcat:    LATE EVOLUTION
    proposal_for:  GO
    longterm:      1
    pi_title:      DR
    pi_fname:      CHARLES
    pi_lname:      ALCOCK
    pi_inst:       INST. OF GEOPHYS. AND PLANETARY PHYS., LLNL
    pi_country:    USA
    pi_phone:      415-423-0666
    keywords_1:    WHITE DWARFS
    hours_pri:     4.60
    num_pri:       1
    fos:           Y
    funds_amount:  76150
    funds_length:  24
    funds_date:    JAN-91
    pi_position:   ASTROPHYS CTR HEAD
    off_fname:     C.
    off_mi:        B
    off_lname:     TARTER
    off_title:     ASSOC DIR OF PHYSICS
    off_inst:      LAWRENCE LIVERMORE NATL. LAB.
    off_addr_1:    P.O. BOX 808, L-295
    off_city:      LIVERMORE
    off_state:     CA
    off_zip:       94550
    off_country:   USA
    off_phone:     415-422-4169
    off_telex:     415-422-9523
! end of coverpage

abstract:

    line_1:        We propose a sensitive search using the FOS for Lyman alpha absorption in the
    line_2:        spectrum of a DB white dwarf star whose visible spectrum shows only helium
    line_3:        absorption lines. The observed absence of H alpha and H beta absorption already
    line_4:        shows that the N(H) to N(He) ratio is less than or equal to 10E(-4). The Lyman
    line_5:        alpha line is approximately 100 times stronger than H alpha (for a given
    line_6:        hydrogen abundance) so the potential upper limit to the hydrogen content is 100
    line_7:        times stronger than presently available. At the same time, we would obtain
    line_8:        senstitive measurements of (or upper limits to) the UV resonance lines of
    line_9:        carbon, magnesium, aluminum, silicon and iron. Detection of or upper limits to
    line_10:       any of these lines would place significant constraints on the models of the
    line_11:       atmospheres of this star, its accretion of interstellar and circumstellar
    line_12:       material, and indirectly on their ages.

!
! end of abstract

general_form_proposers:

  lname:           ALCOCK
    fname:         CHARLES
    title:         DR
    inst:          LAWRENCE LIVERMORE NATL. LAB.
    country:       USA

!
! end of general_form_proposers block

general_form_text:

  question:        3
    section:       1
    line_1:        We will observe a white dwarf with the FOS using the G160L
    line_2:        disperser.  We wish to use the smallest aperature practical
    line_3:        for this star in order to minimize geocoronal Lyman alpha.
    line_4:        Since sky subtraction will be necessary, we will use a pair of
    line_5:        aperatures to collect both object and sky spectra.  The
    line_6:        potential target is in the guide star
    line_7:        catalog which should facilitate acquisition.
    line_8:        Although we specify a single long exposure in the exposure
    line_9:        sheet, the exposure can be broken up as appropriate for
    line_10:       occultation or spacecraft efficiency.

!
!end of general form text

general_form_address:

  lname:           ALCOCK
    fname:         CHARLES
    title:         DR
    category:      PI
    inst:          IGPP - LLNL
    addr_1:        L-413 , P.O.BOX 808
    city:          LIVERMORE
    state:         CA
    zip:           94550
    country:       USA
    phone:         415-423-0666
    from_date:     01-JUL-89
    to_date:       01-JUL-94

!
! end of general_form_address records

fixed_targets:

    targnum:       1
    name_1:        WD1645+325
    descr_1:       STAR
    pos_1:         PLATE-ID = 01G4,
    pos_2:         RA=16H 47M 18.559S +/- 0.5",
    pos_3:         DEC=+32D 28' 32.57" +/- 0.5"
    equinox:       J1984.0
    pm_or_par:     Y
    pos_epoch_yr:  1984.00
    ra_pm_val:     -0.009333
    ra_pm_unct:    0.006667
    dec_pm_val:    0.0600
    dec_pm_unct:   0.0400
    fluxnum_1:     001
    fluxval_1:     V=13.5+/-0.5

!
! end of fixed targets

! No solar system records found

! No generic target records found

exposure_logsheet:

    linenum:       1.000
    targname:      WD1645+325
    config:        FOS/BL
    opmode:        ACQ/BINARY
    aperture:      4.3
    sp_element:    MIRROR
    num_exp:       001
    time_per_exp:  0.35S
    priority:      01
    param_1:       BRIGHT=33000
    req_1:         ONBOARD ACQ FOR 2

!

    linenum:       2.000
    targname:      WD1645+325
    config:        FOS/BL
    opmode:        ACCUM
    aperture:      0.25-PAIR
    sp_element:    G160L
    wavelength:    1150-2524
    num_exp:       001
    time_per_exp:  15238S
    priority:      1
    param_1:       STEP-PATT=STAR-SKY
    comment_1:     THE EXPOSURE CAN BE BROKEN UP
    comment_2:     AS APPROPRIATE.

!
! end of exposure logsheet

! No scan data records found