!  File:  2623C.PROP
!  Database:  PEPDB
!  Date:  17-FEB-1994:09:25:22

coverpage:

  title_1:         A MEASUREMENT OF THE PRIMORDIAL HELIUM ABUNDANCE OF MU-CASSIOPEIAE
    sci_cat:       STELLAR POPULATIONS
    sci_subcat:    ASTROMETRY
    proposal_for:  GO
    longterm:      3
    pi_title:      PROF.
    pi_fname:      DENNIS
    pi_mi:         J.
    pi_lname:      HEGYI
    pi_inst:       MICHIGAN, UNIVERSITY OF
    pi_country:    USA
    pi_phone:      (313)-764-5448
    keywords_1:    POPULATION II, SUBDWARF, BINARY, ASTROMETRY
    hours_pri:     6.74
    num_pri:       10
    wf_pc:         X
    fgs:           X
    funds_amount:  213421
    funds_length:  36
    funds_date:    OCT-89
    pi_position:   PROFESSOR OF PHYSICS
    off_fname:     MARTIN
    off_mi:        H.
    off_lname:     TOBIN
    off_title:     ASSISTANT DIRECTOR
    off_inst:      DIV. OF RESEARH DEVEL. &ADMIN.
    off_addr_1:    THE UNIVERSITY OF MICHIGAN
    off_addr_2:    245 W. ENG. BLDG. 550 E. UNIV. ST
    off_city:      ANN ARBOR
    off_state:     MI.
    off_zip:       481091092
    off_country:   USA
    off_phone:     (313)-763-1268
    off_telex:     432-0815
! end of coverpage

abstract:

    line_1:        At the present time, the primordial helium abundance is the single most
    line_2:        important observable which can be used to test the standard model of the big
    line_3:        bang. The most precise measurements of the primordial helium abundace have
    line_4:        been obtained from extragalactic HII regions. However, many correction are
    line_5:        involved in reducing measured line intensities to helium abundances. Because
    line_6:        the primordial helium abundance plays such an essential role in both cosmology
    line_7:        and astrophysics, it is important to accurately measure it using more than one
    line_8:        method. By applying the stellar mass-luminosity law, we propose to determine
    line_9:        the helium abundance of the astrometric binary Mu-Cas using ST to obtain an
    line_10:       orbit to determine the masses of the stars. Based on simulations, three years
    line_11:       of ST observations would yield a mass uncertainty of the primary star
    line_12:       corresponding to an uncertainty in the helium abundace by mass of 0.006. This
    line_13:       uncertainty could be even further reduced if observations were extended over a
    line_14:       longer interval of time. ST is necessary to achieve the desired measuring
    line_15:       accuracy because astrometric observations of the faint, close secondary with
    line_16:       respect to a background field of stars can only be obtained with ST; since
    line_17:       the secondary has a motion almost five times larger than that of the primary,
    line_18:       its orbit is much less sensitive to unknown systematic effects for the same
    line_19:       measuring precision.

!
! end of abstract

general_form_proposers:

  lname:           DEMARQUE
    fname:         PIERRE
    inst:          YALE UNIVERSITY
    country:       USA

!

  lname:           HEGYI
    fname:         DENNIS
    title:         P.I.
    mi:            J.
    inst:          MICHIGAN, UNIVERSITY OF
    country:       USA

!

  lname:           CRANE
    fname:         PHILIPPE
    inst:          EUROPEAN SOUTHERN OBSERVATORY
    country:       FRG
    esa:           X

!

  lname:           HAYWOOD
    fname:         JAMES
    mi:            W.
    inst:          MICHIGAN, UNIVERSITY OF
    country:       USA

!

  lname:           KURUCZ
    fname:         ROBERT
    mi:            L.
    inst:          CFA
    country:       USA

!

  lname:           SNEDEN
    fname:         CHRISTOPHER
    inst:          TEXAS, UNIVERSITY OF
    country:       USA

!
! end of general_form_proposers block

general_form_text:

  question:        3
    section:       1
    line_1:        We propose to use the FGS to measure the position of HD6582 with respect to 9
    line_2:        reference field stars twice a year for three years.  Each observation consists
    line_3:        of the following sequence.  First, using the F5ND neutral density filter,
    line_4:        HD6582 is observed.  Then that filter is removed, the F583W Astrometry Clear
    line_5:        Filter is inserted, and four of the field stars are observed. Next, HD6582 is
    line_6:        again observed, the 5 remaining field stars are observed, and HD6582 is observed
    line_7:        for the last time.  The neutral density filter is required for each
    line_8:        observation of HD6582.
    line_9:        The separation between Mu-Cas-A and Mu-Cas-B is measured by placing Mu-Cas-A
    line_10:       on the the Baum spot since there is a large magnitude difference between the
    line_11:       stars.  Three exposures are obtained twice each year for three
    line_12:       years.  The three exposures are shifted by a small amount relative to one
    line_13:       another to minimize the consequences of one of the stars falling on a
    line_14:       bad pixel.  Because the observations are separated by 6 months, it will be
    line_15:       necessary to use different guide stars for each of these observations.
    line_16:       Therefore, HD6582 (Mu-Cas) must be acquired interactively once for each set
    line_17:       of guide stars so that two interactive acquisitions will be required.

!
!end of general form text

general_form_address:

  lname:           HEGYI
    fname:         DENNIS
    mi:            J.
    title:         PROF.
    category:      PI
    inst:          UNIVERSITY OF MICHGAN
    addr_1:        500 E. UNIVERSITY
    city:          ANN ARBOR
    state:         MI
    zip:           48109
    country:       USA

!
! end of general_form_address records

fixed_targets:

    targnum:       1
    name_1:        HD6582
    name_2:        (MU_CAS)
    descr_1:       STAR; BINARY; TYPE=G5 V;SUBDWARF
    pos_1:         RA = 1H 4M 55.72S +/- 0.5",
    pos_2:         DEC = +54D 40' 32.8" +/- 0.5"
    equinox:       1950
    pm_or_par:     Y
    pos_epoch_bj:  B
    pos_epoch_yr:  1950.00
    ra_pm_val:     0.229093
    ra_pm_unct:    0.000013
    dec_pm_val:    -1.5787
    dec_pm_unct:   0.0002
    an_prlx_val:   0.1368
    an_prlx_unct:  0.0033
    fluxnum_1:     1
    fluxval_1:     V =5.16 +/- 0.1, TYPE = G5 V

!

    targnum:       2
    name_1:        AST1-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = 161" +/- 3",
    pos_2:         ETA-OFF = -48" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =9 +/- 2

!

    targnum:       3
    name_1:        AST2-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = 159" +/- 3",
    pos_2:         ETA-OFF = -108" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =15 +/- 3

!

    targnum:       4
    name_1:        AST3-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +104" +/- 3",
    pos_2:         ETA-OFF = -150" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =16 +/- 3

!

    targnum:       5
    name_1:        AST4-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +59" +/- 3",
    pos_2:         ETA-OFF = -56" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =13 +/- 3

!

    targnum:       6
    name_1:        AST5-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +37" +/- 3",
    pos_2:         ETA-OFF = -51" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =15 +/- 3

!

    targnum:       7
    name_1:        AST7-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +96" +/- 3",
    pos_2:         ETA-OFF = +15" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =15 +/- 3

!

    targnum:       8
    name_1:        AST8-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +134" +/- 3",
    pos_2:         ETA-OFF = -15" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =15 +/- 3

!

    targnum:       9
    name_1:        AST9-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +88" +/- 3",
    pos_2:         ETA-OFF = -26" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =15 +/- 3

!

    targnum:       10
    name_1:        AST10-REF
    descr_1:       STAR; ASTROMETRIC REFERENCE
    pos_1:         XI-OFF = +104" +/- 3",
    pos_2:         ETA-OFF = -44" +/- 3", FROM 1
    equinox:       1950
    fluxnum_1:     1
    fluxval_1:     V =15 +/- 3

!
! end of fixed targets

! No solar system records found

! No generic target records found

exposure_logsheet:

    linenum:       1.000
    sequence_1:    DEFINE
    sequence_2:    INTMU
    targname:      HD6582
    config:        PC
    opmode:        IMAGE
    aperture:      P8
    sp_element:    F8ND
    num_exp:       1
    time_per_exp:  0.7S
    s_to_n:        170
    fluxnum_1:     1
    priority:      1
    param_1:       PRE-FLASH=YES

!

    linenum:       2.000
    sequence_1:    DEFINE
    sequence_2:    PCMU
    targname:      HD6582
    config:        PC
    opmode:        IMAGE
    aperture:      ALL-ND
    sp_element:    F439W
    num_exp:       1
    time_per_exp:  0.7S
    s_to_n:        170
    fluxnum_1:     1
    priority:      1
    param_1:       PRE-FLASH=YES
    req_1:         SEQ 2-4 NON-INT;
    req_2:         POS TARG 16.8, -16.8

!

    linenum:       3.000
    sequence_1:    DEFINE
    sequence_2:    PCMU
    targname:      HD6582
    config:        PC
    opmode:        IMAGE
    aperture:      ALL-ND
    sp_element:    F439W
    num_exp:       1
    time_per_exp:  0.7S
    s_to_n:        170
    fluxnum_1:     1
    priority:      1
    param_1:       PRE-FLASH=YES
    req_1:         POS TARG 17.1, -16.8

!

    linenum:       4.000
    sequence_1:    DEFINE
    sequence_2:    PCMU
    targname:      HD6582
    config:        PC
    opmode:        IMAGE
    aperture:      ALL-ND
    sp_element:    F439W
    num_exp:       1
    time_per_exp:  0.7S
    s_to_n:        170
    fluxnum_1:     1
    priority:      1
    param_1:       PRE-FLASH=YES
    req_1:         POS TARG 16.8, -17.1

!

    linenum:       5.000
    sequence_1:    USE INTMU
    req_1:         INT ACQ FOR 6;
    req_2:         POS TARG 10,-10

!

    linenum:       6.000
    sequence_1:    USE PCMU
    req_1:         GROUP 6, 21 WITHIN 3D;
    req_2:         AT 1-FEB-91 +/- 5D

!

    linenum:       7.000
    sequence_1:    USE INTMU
    req_1:         INT ACQ FOR 8

!

    linenum:       8.000
    sequence_1:    USE PCMU
    req_1:         GROUP 8, 22 WITHIN 3D;
    req_2:         AT 3-AUG-91 +/- 5D;

!

    linenum:       9.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      HD6582
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F5ND
    num_exp:       1
    time_per_exp:  5.2S
    s_to_n:        100
    fluxnum_1:     1
    priority:      1
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=0.1
    req_1:         SEQ 9-20 NON-INT

!

    linenum:       10.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST1-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  5.2S
    s_to_n:        100
    fluxnum_1:     1
    priority:      1
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=0.1

!

    linenum:       11.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST2-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  53.2S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=1.6

!

    linenum:       12.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST3-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  104.4S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=3.2

!

    linenum:       13.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST4-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  14.8S
    s_to_n:        50
    fluxnum_1:     1
    priority:      1
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=0.4

!

    linenum:       14.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      HD6582
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F5ND
    num_exp:       1
    time_per_exp:  5.2S
    s_to_n:        100
    fluxnum_1:     1
    priority:      1
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=0.1

!

    linenum:       15.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST5-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  53.2S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=1.6

!

    linenum:       16.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST7-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  53.2S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=1.6

!

    linenum:       17.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST8-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  53.2S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=1.6

!

    linenum:       18.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST9-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  53.2S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=1.6

!

    linenum:       19.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      AST10-REF
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F583W
    num_exp:       1
    time_per_exp:  53.2S
    s_to_n:        50
    fluxnum_1:     1
    priority:      2
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=1.6

!

    linenum:       20.000
    sequence_1:    DEFINE
    sequence_2:    ASTROM
    targname:      HD6582
    config:        FGS
    opmode:        POS
    aperture:      PRIME
    sp_element:    F5ND
    num_exp:       1
    time_per_exp:  5.2S
    s_to_n:        100
    fluxnum_1:     1
    priority:      1
    param_1:       DATA-RATE=32,
    param_2:       FES-TIME=0.1

!

    linenum:       21.000
    sequence_1:    USE
    sequence_2:    ASTROM
    req_1:         AT 1-FEB-91 +/- 5D;

!

    linenum:       22.000
    sequence_1:    USE
    sequence_2:    ASTROM
    req_1:         AT 3-AUG-91 +/- 5D;
    req_2:         CYCLE 1 / 6, 8, 21, 22

!

    linenum:       23.000
    sequence_1:    USE PCMU
    req_1:         GROUP 23, 25 WITHIN 3D;
    req_2:         AT 1-FEB-92 +/- 5D

!

    linenum:       24.000
    sequence_1:    USE PCMU
    req_1:         GROUP 24, 26 WITHIN 3D;
    req_2:         AT 2-AUG-92 +/- 5D;

!

    linenum:       25.000
    sequence_1:    USE
    sequence_2:    ASTROM
    req_1:         AT 1-FEB-92 +/- 5D;

!

    linenum:       26.000
    sequence_1:    USE
    sequence_2:    ASTROM
    req_1:         AT 2-AUG-92 +/- 5D;
    req_2:         CYCLE 2 / 23, 24, 25, 26

!

    linenum:       27.000
    sequence_1:    USE PCMU
    req_1:         GROUP 27, 29 WITHIN 3D;
    req_2:         AT 1-FEB-93 +/- 5D

!

    linenum:       28.000
    sequence_1:    USE PCMU
    req_1:         GROUP 28, 30 WITHIN 3D;
    req_2:         AT 3-AUG-93 +/- 5D;

!

    linenum:       29.000
    sequence_1:    USE
    sequence_2:    ASTROM
    req_1:         AT 1-FEB-93 +/- 5D;

!

    linenum:       30.000
    sequence_1:    USE
    sequence_2:    ASTROM
    req_1:         AT 3-AUG-93 +/- 5D;
    req_2:         CYCLE 3 / 27, 28, 29, 30

!
! end of exposure logsheet

! No scan data records found