7999(  1) - 04/16/98 14:13  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7999
                                                       Version: 1
                                                       Check-in Date: 16-Apr-1998
                                                                      14:10:00

1.Proposal Title:
Implications of the "Missing UV Opacity" on Beryllium and Boron Abundance
Determinations
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2. Proposal For  3. Cycle
AR               7
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4. Investigators
                                                                                     Contact?
    PI: GLENN SCHNEIDER                   STEWARD OBSERVATORY
   CoI: Roger Bell                        University of Maryland                        N

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5. Abstract

A persistent puzzle in our understanding of the UV stellar spectrum has been the
inability of theoretical models to match the observed flux: the missing UV opacity
problem. This lack of understanding inhibits our exploitation of the UV region; the
study of stellar populations in external galaxies, the search for hot stars in
crowded globular cluster cores, and most directly the derivation of important
elemental abundances such as beryllium and boron with transitions only in the UV. We
have recently addressed this problem in the Sun and devised an empirical scheme to
quantify the missing opacity (Balachandran and Bell 1998). An important consequence
of our finding has been that the solar beryllium abundance equals the meteoritic
value and is not depleted as claimed by studies over the last 20 years. Our result
strongly suggest that the extensive recent publications of beryllium and boron
abundances based on GHRS data are systematically in error. Here we propose to use
the GHRS archives to characterize the missing opacity as a function of temperature,
metallicity and wavelength. We will then rederive boron abundances in key stars.
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  Data Distribution

  Media:           ELECTRONIC
  Blocking Factor: 10
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                                                7999(  1) - 04/16/98 14:13  - [  2]

            Summary Form for Proposal  7999

  Item                         Used in this proposal
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  Proposal Category            AR
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