!   $Id: 5220,v 30.1 1994/07/27 16:00:08 pepsa Exp $

coverpage:

  title_1:         THE AURORA AND AIRGLOW OF URANUS
    sci_cat:       SOLAR SYSTEM
    sci_subcat:    GIANT PLANETS
    proposal_for:  GTO/WF2
    pi_title:      DR.
    pi_fname:      JOHN
    pi_lname:      TRAUGER
    pi_inst:       2370
    pi_country:    USA
    pi_phone:      818-354-9594
    keywords_1:    JUPITER
    hours_pri:     1.48
    num_pri:       1
    wf_pc:         Y
    time_crit:     Y
    pi_position:   PROJECT SCIENTIST
    off_fname:     JOHN
    off_mi:        T.
    off_lname:     TRAUGER
    off_title:     DR.
    off_inst:      JET PROPULSION LABORATORY
    off_addr_1:    4800 OAK GROVE DRIVE
    off_addr_2:    MAIL STOP 179-225
    off_city:      PASADENA
    off_state:     CA
    off_zip:       91109
    off_country:   USA
    off_phone:     818-354-9594
! end of coverpage

abstract:

    line_1:        WFPC2 observations of Uranus in the FUV will show the spatial
    line_2:        distribution of the H Ly a and H2 Lyman and Werner band emissions
    line_3:        with 20-80 pixels across the disk (depending on read-out and
    line_4:        limiting sensitivity).  The Uranus aurora are known to be variable,
    line_5:        but present in the sunlit hemisphere, and spatial variations in
    line_6:        the airglow emission appear in the Voyager UVS data.  We will
    line_7:        have a good sensitivity to discrete auroral regions, or ovals,
    line_8:        and best measure the airglow emissions near the limb where they
    line_9:        are enhanced in both optical depth and brightness.  We will also
    line_10:       study the extended H cloud (and in cycle 5 the possible OH cloud)
    line_11:       coming from Uranus and its ring/satellite system.   This proposal
    line_12:       is the first phase of a WFPC2 GTO program on Uranus.

!
! end of abstract

general_form_proposers:

  lname:           TRAUGER
    fname:         JOHN
    title:         DR.
    mi:            T.
    inst:          2370
    country:       USA
    esa:           N

!

  lname:           CLARKE
    fname:         JOHN
    title:         PROF.
    mi:            T.
    inst:          2660
    country:       USA
    esa:           N

!

  lname:           BURROWS
    fname:         CHRIS
    inst:          STSCI
    country:       USA

!

  lname:           CRISP
    fname:         DAVID
    inst:          JPL
    country:       USA

!

  lname:           HOESSEL
    fname:         JOHN
    inst:          UNIV. OF WISCONSIN
    country:       USA

!

  lname:           GALLAGHER
    fname:         JAY
    inst:          UNIV. OF WISCONSIN
    country:       USA

!

  lname:           GRIFFITHS
    fname:         RICHARD
    inst:          JOHNS HOPKINS UNIV
    country:       USA

!

  lname:           HESTER
    fname:         JEFF
    inst:          ARIZONA STATE UNIV.
    country:       USA

!

  lname:           HOLTZMAN
    fname:         JOHN
    inst:          LOWELL OBSERVATORY
    country:       USA

!

  lname:           MOULD
    fname:         JEREMY
    inst:          CALTECH
    country:       USA

!

  lname:           WESTPHAL
    fname:         JAMES
    inst:          CALTECH
    country:       USA

!
! end of general_form_proposers block

general_form_text:


!

  question:        3
    section:       1
    line_1:        Uranus is roughly as bright as Saturn in its FUV emissions, and has
    line_2:        a much higher reflectivity over 1500-2100 A.  Auroral/airglow images
    line_3:        with the WFC will give 40 pixels across the 3.8 arcsec disk, and the
    line_4:        2x2 readout may be used for good sensitivity above the read noise.
    line_5:        We will use F160W with and without F130LP to separate the optically
    line_6:        thick H Lya from the optically thin H2 band emissions.  Images with
    line_7:        F160W and F165LP will measure the reflected solar component for
    line_8:        subtraction from the images, and may show haze absorption. Short
    line_9:        F673N  images will register the limb position.   The FUV images
    line_10:       should reveal for the first time the spatial distribution of the
    line_11:       UV emissions to identify their auroral and airglow components.
    line_12:       The altitude resolution will be limited, but we may still find
    line_13:       azimuthal variations in the limb airglow brightness arising from
    line_14:       possible strong conjugate plasma flows across the terminator
    line_15:       resulting from Uranus' particular magnetic field geometry.   The
    line_16:       images will also be co-added to image the extended H atmosphere in
    line_17:       Ly a resonant scattering, and we can search for different scale
    line_18:       heights in different directions revealing different exobase
    line_19:       temperatures.  Voyager data suggested UV auroral hot spots on
    line_20:       Uranus that would be presently observable from Earth for ~30% of
    line_21:       the time.  Recent IR observations of H3+ emissions from Uranus may
    line_22:       show evidence for auroral related structure, in which case we would
    line_23:       time the HST observations optimized to view the aurora.

!

  question:        4
    section:       1
    line_1:        The far-UV emissions of Uranus's aurora and airglow can only be
    line_2:        recorded from a space-based platform due to atmospheric absorption.
    line_3:        The UV emissions are important because they are directly excited by
    line_4:        the precipitating energetic articles.  IUE has observed temporal
    line_5:        variations in the disk-integrated H Ly a emissions for which the
    line_6:        emitting region area has not been identified.   It is therefore
    line_7:        important to image these emissions with HST to resolve the auroral
    line_8:        component, which would be spatially confined.  The near-IR H3+
    line_9:        emissions from Uranus detected with ground-based telescopes should
    line_10:       have an auroral component but these emissions can also be thermally
    line_11:       excited by non-auroral processes, and are thus not sufficient to
    line_12:       resolve the morphology of the primary auroral processes.   In
    line_13:       addition, 2x2 WF images would have at least a factor of two better
    line_14:       spatial resolution than the ground-based H3+ images.   The extended
    line_15:       hydrogen corona particular to Uranus can only be detected in the UV.

!

  question:        5
    section:       1
    line_1:        The Voyager UV data show indication of auroral hot spots on Uranus'
    line_2:        dayside that would be visible from Earth at present for only about
    line_3:        30% of the time.  There may of course be additional auroral emission
    line_4:        regions which were not active during the Voyager encounter.   The
    line_5:        large uncertainty in the rotation period does not allow prediction
    line_6:        of the visibility of the auroral region from the Earth extended from
    line_7:        the Voyager data in 1986.   Recent IR observations of H3+ emissions
    line_8:        from Uranus may show evidence for auroral related structure, and we
    line_9:        will use any information derived from these H3+ observations to
    line_10:       optimize the time of the HST observations to view the aurora.
    line_11:       We will also try to coordinate simultaneous ground-based imaging of
    line_12:       the H3+ emissions and the WFPC2 images of the aurora.
    line_13:       This will be important to determine the relation between the
    line_14:       different emission processes in Uranus' ionosphere.

!

  question:        6
    section:       1
    line_1:        Scheduling during dark time is required. We are imaging FUV
    line_2:        emissions from H (Lyman alpha) and H2 (Lyman and Werner bands),
    line_3:        some very weak emissions, and therefore require minimum
    line_4:        contamination from geocoronal Ly a and oxygen airglow emissions
    line_5:        in order to obtain the best possible S/N.
    line_6:        The exposures cannot be interrupted because of Uranus's fast
    line_7:        rotation (~17.24 hours) and known temporal variability in the
    line_8:        emissions, and the exposures series have been planned accordingly.

!


!

  question:        8
    section:       1
    line_1:        NONE

!

  question:        9
    section:       1
    line_1:        No images of Uranus in the UV have been obtained with HST or any
    line_2:        other instrument.  We estimate that WFPC2 with the Na metal
    line_3:        filter will have 4-5 times higher efficiency and a much larger
    line_4:        dynamic range than would be possible with the FOC.

!

  question:        10
    section:       1
    line_1:        Unix workstations are available with IDL and the WFPC2 system
    line_2:        SPICA software packages.

!

  question:        13
    section:       1
    line_1:        Uranus and Neptune form a class of giant planet substantially
    line_2:        smaller than Jupiter and Saturn, with much colder lower atmospheres
    line_3:        (changing the composition), and with bizarrely tilted and offset
    line_4:        magnetic fields.  Uranus is roughly as bright as Saturn in the FUV
    line_5:        despite being twice as far from the Sun and can be imaged with
    line_6:        WFPC2.   In addition to bright and highly variable FUV airglow and
    line_7:        auroral emissions, Uranus has an extensive hydrogen corona resulting
    line_8:        from the planet's low gravity and hot (~800K) upper atmospheric
    line_9:        temperature.  IUE has observed strong and highly variable H Ly a
    line_10:       emissions from Uranus, and it is now known from Voyager and IUE data
    line_11:       that these emissions are composed of resonant scattering components
    line_12:       combined with poorly understood airglow and auroral emissions.
    line_13:       The difficulty in understanding the observed variations with time is
    line_14:       due in part to the lack of spatial resolution combined with a large
    line_15:       uncertainty in the planetary (magnetic) rotation period of 17.24 +/-
    line_16:       0.01 hours derived in 1986 from Voyager data.   We will therefore
    line_17:       attempt to resolve the spatial distribution of the H Ly a and the H2
    line_18:       auroral and airglow emissions and help understand the nature of
    line_19:       the observed changes with time with WFPC2 images in cycle 4.
    line_20:       In cycle 5, with repeated FUV observations we will study the
    line_21:       temporal variations and may refine Uranus' rotational period.  We
    line_22:       may also image (in the NUV) Uranus' extended OH cloud sputtered
    line_23:       from the icy ring particles and/or satellites.

!
!end of general form text

general_form_address:

  lname:           TRAUGER
    fname:         JOHN
    mi:            T.
    title:         DR.
    category:      PI
    inst:          2370
    addr_1:        MS 179-225
    addr_2:        4800 Oak Grove Drive
    city:          Pasadena
    state:         CA
    zip:           91109
    country:       USA
    phone:         818-354-9594

!

  lname:           CLARKE
    fname:         JOHN
    mi:            T.
    title:         DR.
    inst:          2660
    phone:         313-747-3540

!

  lname:           BALLESTER
    fname:         GILDA
    mi:            E.
    title:         DR.
    inst:          2660
    phone:         313-747-3670

!
! end of general_form_address records

! No fixed target records found

solar_system_targets:

  targnum:         1
    name_1:        URANUS-AUR1
    descr_1:       PLANET URANUS
    lev1_1:        STD = URANUS
    wind_1:        OLG OF URANUS BETWEEN 330 60
    comment_1:     URANUS AURORA/AIRGLOW FUV IMAGES WITH
    comment_2:     WFC AND WITH 2 FILTER COMBINATIONS TO
    comment_3:     BE MADE IN SEQUENTIAL ORBITS.
    comment_4:     THE F160BW EXPOSURES SHOULD SCHEDULED
    comment_5:     ACCORDING TO THE LATEST POSSIBLE
    comment_6:     INFORMATION ON H3+ IR OBSERVATIONS TO
    comment_7:     HAVE BEST CHANCE TO OBSERVE THE AURORA.
    comment_8:     OLG WINDOWS CAN BE EXPANDED SOMEWHAT
    comment_9:     IF NEEDED FOR SCHEDULING.
    comment_10:    SCHEDULE DURING DARK TIME.
    fluxnum_1:     1
    fluxval_1:     V = -0.6 +/- 0.5
    fluxnum_2:     2
    fluxval_2:     F-LINE(1400)=1+/-3E-14,W-LINE(1400)=420
    fluxnum_3:     3
    fluxval_3:     F-CONT(1800) = 2 +/- 5 E-13
    fluxnum_4:     4
    fluxval_4:     SIZE = 3.9 +/- 1
    fluxnum_5:     5
    fluxval_5:     F-CONT(5500) = 2.1 +/- 1 E-12
    fluxnum_6:     6
    fluxval_6:     SIZE = 1.1

!
! end of solar system targets

! No generic target records found

exposure_logsheet:

    linenum:       1.100
    targname:      URANUS-AUR1
    config:        WFPC2
    opmode:        IMAGE
    aperture:      WF4-FIX
    sp_element:    F673N
    num_exp:       1
    time_per_exp:  12.0 S
    s_to_n:        120
    fluxnum_1:     5
    fluxnum_2:     6
    priority:      1
    param_1:       ATD-GAIN = 15
    param_2:       CR-SPLIT=NO
    req_1:         CYCLE 4;
    req_2:         GROUP 1.1 - 1.5 NO GAP;
    req_3:         PCS MODE F;
    req_4:         POS TARG -4.2,0.0 /1.1-1.5
    comment_1:     RED IMAGES OF URANUS WITH SAME GUIDE
    comment_2:     STARS AS IN LINENUM 1.2 TO
    comment_3:     IDENTIFY LIMB OF PLANET.

!

    linenum:       1.200
    targname:      URANUS-AUR1
    config:        WFPC2
    opmode:        IMAGE
    aperture:      WF4-FIX
    sp_element:    F160BW, F165LP
    num_exp:       1
    time_per_exp:  1000.0 S
    s_to_n:        3
    fluxnum_1:     3
    fluxnum_2:     4
    priority:      1
    param_1:       ATD-GAIN = 7
    param_2:       CR-SPLIT=NO
    req_1:         CYCLE 4;
    req_2:         PCS MODE F
    comment_1:     IMAGE OF URANUS' BACKGROUND UV
    comment_2:     SCATTERED LIGHT TO SUBTRACT FROM FUV
    comment_3:     IMAGES OF AURORA.

!

    linenum:       1.300
    targname:      URANUS-AUR1
    config:        WFPC2
    opmode:        IMAGE
    aperture:      WF4-FIX
    sp_element:    F160BW
    num_exp:       4
    time_per_exp:  1000.0 S
    s_to_n:        10
    fluxnum_1:     2
    fluxnum_2:     3
    fluxnum_3:     4
    priority:      1
    param_1:       ATD-GAIN = 7
    param_2:       CR-SPLIT=NO
    req_1:         CYCLE 4;
    req_2:         PCS MODE F
    comment_1:     FUV IMAGE OF URANUS' AURORA/AIRGLOW
    comment_2:     H AND H2 EMISSIONS.  DARK TIME.

!

    linenum:       1.400
    targname:      URANUS-AUR1
    config:        WFPC2
    opmode:        IMAGE
    aperture:      WF4-FIX
    sp_element:    F160BW, F165LP
    num_exp:       1
    time_per_exp:  1000.0 S
    s_to_n:        10
    fluxnum_1:     2
    fluxnum_2:     3
    fluxnum_3:     4
    priority:      1
    param_1:       ATD-GAIN = 7
    param_2:       CR-SPLIT=NO
    req_1:         CYCLE 4;
    req_2:         PCS MODE F
    comment_1:     FUV IMAGE OF URANUS' AURORA/AIRGLOW
    comment_2:     H AND H2 EMISSIONS. DARK TIME.

!
    linenum:       1.500
    targname:      URANUS-AUR1
    config:        WFPC2
    opmode:        IMAGE
    aperture:      WF4-FIX
    sp_element:    F673N
    num_exp:       1
    time_per_exp:  12.0 S
    s_to_n:        120
    fluxnum_1:     5
    fluxnum_2:     6
    priority:      1
    param_1:       ATD-GAIN = 15
    param_2:       CR-SPLIT=NO
    req_1:         CYCLE 4;
    req_2:         PCS MODE F
    comment_1:     RED IMAGES OF URANUS WITH SAME GUIDE
    comment_2:     STARS AS IN LINENUM 1.4 TO
    comment_3:     IDENTIFY LIMB OF PLANET AND TELESCOPE
    comment_4:     POINTING.

!
! end of exposure logsheet

! No scan data records found