5811(  0) - 07/18/95 18:04  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      5811
                                                       Version: **********
                                                       Check-in Date: **********

1.Proposal Title:
A Search for Stellar Duplicity and Variability from FGS Guide Star Acquisitions and
Guiding Data
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2. Scientific Category   3. Proposal For  4. Cycle
Stellar Populations         AR               5
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5. Investigators
                                                                                     Contact?
    PI: Dr. Glenn Schneider               Steward Observatory, University of Arizona
   CoI: Dr. John Hershey                  Computer Sciences Corporation                 N
   CoI: Michael Wenz                      Computer Sciences Corporation                 N

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6. Abstract

The HST Fine Guidance Sensors (FGS) have the unique astrometric capabilities of
revealing faint companions in close binary systems, and measuring their position
angles and component separations with a precision which far exceeds that which is
possible using any ground based techniques. In addition, the intensity data which
are produced by the FGS PMTs while in fine lock provide high precision relative
photometry on rapid time scales.  In previous HST observing Cycles, while in guiding
mode, these FGS data were telemetered to the ground at a 1 Hz rate.  In mid Cycle 4
a new telemetry format will be adopted for all normal operations which will provide
these astrometric and photometric data at 40 Hz for all guide star acquisitions and
periods of active guiding. We propose to examine these engineering data, obtained
from the HST archive, to perform a serendipitous search for stellar duplicity to
determine the incidence of doubles in the Guide Star Catalog as well as the
separations, position angles, and relative brightnesses of the individual stellar
components in such binaries.  We will also examine the light curves and power
spectra of the photometric data in an effort to perform an astroseismological survey
of these stars, as well as look for and characterize variations due to other
intrinsic mechanisms.
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  Observations Description
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  Real Time Justification
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  Calibration Justification
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  Additional Comments
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                                                5811(  0) - 07/18/95 18:04  - [  2]

  Data Distribution

  Media:           8MM
  Blocking Factor: 10
  Ship To:         PI_Address
  Ship Via:        UPS
  Email:                                                              ,
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                                                5811(  0) - 07/18/95 18:04  - [  3]

            Summary Form for Proposal  5811

  Item                         Used in this proposal
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  Proposal Category            AR
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  Scientific Category          Stellar Populations
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