!   $Id: 5314,v 8.1 1994/11/07 14:25:50 pepsa Exp $

coverpage:

  title_1:         THE RED EDGE OF THE ZZ CETI INSTABILITY STRIP
    sci_cat:       COOL STARS
    sci_subcat:    PULSATING STARS
    proposal_for:  GO
    pi_fname:      GERARD
    pi_lname:      VAUCLAIR
    pi_inst:       OBSERVATOIRE MIDI PYRENEES
    pi_country:    FRANCE
    pi_phone:      33-61-332953
    hours_pri:     1.00
    num_pri:       1
    fos:           Y
    off_fname:     MICHEL
    off_lname:     BLANC
    off_title:     DIRECTOR
    off_inst:      5474
    off_addr_1:    14 AV. E. BELIN
    off_city:      31400 TOULOUSE
    off_country:   FRANCE
! end of coverpage

abstract:

    line_1:        ZZ Ceti stars are variable white dwarfs of spectral type DA. The
    line_2:        theoretically predicted instability strip depends on several
    line_3:        uncertain assumptions, most importantly the efficiency of
    line_4:        convective energy transport and the detailed structure of the
    line_5:        outer stellar layers. Empirical determinations from optical
    line_6:        spectra are not as accurate as desirable, because the Balmer
    line_7:        lines reach maximum strengths within the instability strip and
    line_8:        vary only little with temperature. The UV spectrum is much
    line_9:        better suited since we have recently improved the quantitative
    line_10:       description of the quasi-molecular satellite features, that vary
    line_11:       strongly with temperature and should ultimately allow an
    line_12:       accuracy of 200 K. Observations for G117-B15A (defining the hot
    line_13:       edge of the instability strip) have been obtained in Nov. 92.
    line_14:       In this project, we propose to observe BPM30551, one of the
    line_15:       coolest ZZ Ceti stars.

!
! end of abstract

general_form_proposers:

  lname:

!
! end of general_form_proposers block

general_form_text:

  question:        3
    section:       1
    line_1:        We want to obtain spectral coverage of the range dominated by the
    line_2:        Lyman alpha red wing satellites, i.e. 1300 - 2500 A, for the
    line_3:        variable white dwarf BPM30551. With FOS and the G160L grating we
    line_4:        will achieve a S/N of >15 for BPM30551 around 1500 A, where a
    line_5:        secondary flux maximum between the 1400 and 1600 A satellites is
    line_6:        extremely temperature sensitive. For lambda > 1650 A the flux
    line_7:        rises steeply in the star, and the expected S/N ranges from 30 to
    line_8:        80. We will use the ACCUM mode for this object.

!

  question:        3
    section:       2
    line_1:

!

  question:        4
    section:       1
    line_1:        Numerous attempts to determine the boundaries of the instability
    line_2:        strip have been performed with optical or IUE data, among others
    line_3:        also by one of the current CO-PI's (Weidemann and Koester 1984,
    line_4:        Astron.Astrophys.  132, 195). A recent summary of these studies
    line_5:        is given in Wesemael et al. 1991 (White Dwarfs, Nato ASI Series
    line_6:        C, Vol.336, p.159).
    line_8:        The red edge of the instability strip is unfortunately defined by
    line_9:        4 different stars in 4 studies, the coolest ones being BPM30551
    line_10:       and G255-2 around 10000 K (with large uncertainties), while the
    line_11:       next coolest stars do only appear above 11000 K, thus precluding
    line_12:       any firm conclusions from a comparison with observations.
    line_14:       With V = 15.3 and a very steeply declining flux shortward of 1650
    line_15:       A BPM30551 is too faint to give a useful spectrum with the IUE
    line_16:       satellite.  For an accurate temperature determination and
    line_17:       possibly also a determination of the surface gravity (and thus
    line_18:       mass) from the relative strength of the Lyman alpha satellites we
    line_19:       will need an average S/N of about 20 in the UV.

!

  question:        5
    section:       1
    line_1:

!

  question:        6
    section:       1
    line_1:

!


!

  question:        8
    section:       1
    line_1:

!

  question:        9
    section:       1
    line_1:        The first observations (in the White Dwarf Consortium Project)
    line_2:        were obtained in June 1992. D.Koester and N.Allard are
    line_3:        currently working on the analysis of spectra for L745-46A,
    line_4:        together with N.Feautrier (Meudon). This project is not related to
    line_5:        the current proposal.
    line_7:        Related to the present project, G117-B15A has been observed and
    line_8:        the data are being analyzed. G255-2 might be observed during
    line_9:        Cycle 3, but the program received Medium priority.

!

  question:        10
    section:       1
    line_1:        Observatoire Midi-Pyrenees provides computing facilities and
    line_2:        basic support for G. Vauclair.
    line_4:        The Observatoire de Meudon provides computing facilities and
    line_5:        basic support (secretarial, technical programming etc.) for
    line_6:        N. Allard.
    line_8:        The computing facilities of the Institut fuer Theoretische Physik
    line_9:        und Sternwarte (University of Kiel) will also be available for
    line_10:       this project free of charge.

!
!end of general form text

general_form_address:

  lname:           VAUCLAIR
    fname:         GERARD
    category:      PI
    inst:          5474
    addr_1:        OBSERVATOIRE MIDI PYRENEES
    addr_2:        LABORATOIRE D'ASTROPHYSIQUE DE TOULOUSE
    addr_3:        14, AV. E. BELIN, F-31400 TOULOUSE
    city:          TOULOUSE
    country:       FRANCE
    phone:         33-61-332953

!

  lname:
    category:      CON

!
! end of general_form_address records

fixed_targets:

    targnum:       1
    name_1:        WD0104-464
    name_2:        BPM30551
    descr_1:       A,
    descr_2:       120,
    descr_3:       177
    pos_1:         RA  =  01H06M53.241S +/- 0.3",
    pos_2:         DEC = -46D8'55.29"  +/- 0.3",
    pos_3:         PLATE-ID = 04FI
    equinox:       2000
    pm_or_par:     Y
    pos_epoch_bj:  B
    pos_epoch_yr:  1979.70
    ra_pm_val:     0.021300
    dec_pm_val:    0.0800
    comment_1:     RA_PM_VAL IS IN TIME-SEC/YR
    comment_2:     AS DEMANDED IN THE HANDBOOK
    fluxnum_1:     1
    fluxval_1:     V = 15.26 +/- 0.05
    fluxnum_2:     2
    fluxval_2:     F-CONT(1700) = 8.00 +/- 0.5 E-15

!
! end of fixed targets

! No solar system records found

! No generic target records found

exposure_logsheet:

    linenum:       1.000
    targname:      WD0104-464
    config:        FOS/BL
    opmode:        ACQ/BINARY
    aperture:      4.3
    sp_element:    MIRROR
    num_exp:       1
    time_per_exp:  10.0S
    fluxnum_1:     1
    priority:      1
    param_1:       NTHSTAR=1
    req_1:         CYCLE 4 / 1.0-3.0;
    req_2:         ONBOARD ACQ FOR 2.0;

!

    linenum:       2.000
    targname:      WD0104-464
    config:        FOS/BL
    opmode:        ACQ/PEAK
    aperture:      0.3
    sp_element:    MIRROR
    num_exp:       1
    time_per_exp:  2.0S
    fluxnum_1:     1
    priority:      1
    param_1:       TYPE=UP
    param_2:       SEARCH-SIZE-X=5
    param_3:       SEARCH-SIZE-Y=5
    param_4:       SCAN-STEP-X=.172
    param_5:       SCAN-STEP-Y=.172
    req_1:         ONBOARD ACQ FOR 3.0

!

    linenum:       3.000
    targname:      WD0104-464
    config:        FOS/BL
    opmode:        ACCUM
    aperture:      0.3
    sp_element:    G160L
    wavelength:    1600
    num_exp:       1
    time_per_exp:  38.3M
    fluxnum_1:     2
    priority:      1

!
! end of exposure logsheet

! No scan data records found