Status Report

Hubble Space Telescope Daily Report #2768 12/13/00

By SpaceRef Editor
December 13, 2000
Filed under ,

PERIOD COVERED:  0000Z (UTC) 12/12/00 – 0000Z (UTC) 12/13/00
Daily Status Report as of 348/0000Z
    1.1 Completed WF/PC-2/STIS/CCD 8641 (Testing the Accelerating Universe)
        The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were used to observe Type Ia supernovae which provide evidence for an accelerating universe: an extraordinary result that needs to be rigorously tested.  The observations completed with no reported problems.
    1.2 Completed WF/PC-2 8816 (Cycle 9 UV Earthflats)
        The WF/PC-2 was used to obtain sequences of earth streak flats to improve the quality of pipeline flat fields for the WFPC2 UV filter set and in order to monitor flat field stability.  There were no reported problems.
    1.3 Completed WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)
        The WF/PC-2 was used to obtain three dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels.  The proposal completed nominally.
    1.4 Completed WF/PC-2 8390 (Expansion Parallax Distances to Planetary Nebulae)
        The WF/PC-2 was used to make observations of the planetary nebula NGC7662 in order to study its parallax distance.  The largest impediment to our understanding of planetary nebulae is the lack of reliable
distances.  The observations were executed as scheduled, and no anomalies were noted.
    1.5 Completed Three Sets of STIS/CCD 8562 (Probing the Large Scale Structure: Cosmic Shear Observations)
        The Space Telescope Imaging Spectrograph (CCD) was used to probe the distortion of light bundles from distant galaxies, looking at the statistical properties of the intervening inhomogeneous {dark} matter distribution.  The proposal completed nominally.
    1.6 Completed WF/PC-2 8811 (Cycle 9 Standard Darks)
        The WF/PC-2 was used to obtain dark frames every week in order to provide data for the ongoing calibration of the CCD dark current rate, and to monitor and characterize the evolution of hot pixels.  Over an extended period these data will also provide a monitor of radiation damage to the CCDs.  The proposal completed with no reported problems.
    1.7 Completed STIS/CCD 8838 (Bias Monitor – Part 1)
        The Space Telescope Imaging Spectrograph (CCD) was used to monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.  The proposal completed nominally.
    1.8 Completed STIS/CCD/MA2 8770 (The Nucleosynthesis of Boron – Benchmarks for the Galactic Disk)
        The Space Telescope Imaging Spectrograph (CCD and MA2) was used to determine boron (B) abundance.  In spite of several HST cycles of B abundance determinations, we do not know the true, ambient, present-day abundance of B.  Only two stars {with undepleted Li and Be} have been observed to derive the Population I true B abundance.  Past cycles have focused on {1} halo stars with low metallicity and {2} solar-type stars with Li and/or Be deficiencies.  In this proposal, the stellar abundances of B will be determined, measured from the B I 2497 Angstrom line from STIS echelle spectra, of main sequence F-G stars that have retained their full initial abundances of boron.  Our target stars are those for which ground-based observations show that beryllium is undepleted.  These new abundances will map evolution of the B abundance in the Galactic disk in the metallicity range from one-third solar up to solar.  Then the B, and previously determined Li and Be abundances, will be used to improve understanding of the nucleosynthesis of B.  There were no reported anomalies.
    1.9 Completed WF/PC-2 8805 (POMS Test Proposal: WFII Parallel Archive Proposal Continuation)
        The WF/PC-2 was used to perform a generic target version of the WFPC2 Archival Pure Parallel program.  The program will be used to take parallel images of random areas of the sky, following the recommendations of the Parallels Working Group.  The proposal completed with no reported problems.
    1.10 Completed Two Sets of WF/PC-2 8601 (A Snapshot Survey of Probable Nearby Galaxies)
        The WF/PC-2 was used to continue the very successful snapshot survey in order to use the high spatial resolution of HST to determine whether selected galaxies are nearby on the basis of resolution into stars, and the magnitudes and colors of the brightest stars.  There were no reported problems.
    1.11 Completed STIS/CCD 8291 (The Alpha-Element/Iron Ratio in Starburst Populations)
        The Space Telescope Imaging Spectrograph (CCD) was used to observe A and F supergiants in NGC1569, the closest starburst galaxy.  Spectra around 6200 Angstrom taken with the G750M grating will be used to determine element abundances of Fe and several Alpha-elements.  The galaxy has experienced a strong starburst over the past few hundred Myr and possibly only very few and much less intense episodes of star formation at earlier epochs.  Chemical evolution models predict a significant Alpha/Fe enhancement in the galaxy.  The proposal completed with no reported anomalies.
    1.12 Completed WF/PC-2 8059 (POMS Test Proposal: Targeted Parallel Archive Proposal)
        The WF/PC-2 was used to observe the parallel opportunities available in the neighborhood of bright galaxies are treated in a slightly different way from the normal pure parallels.  Local Group galaxies offer the opportunity for a closer look at young stellar
populations.  Narrow-band images in F656N can be used both to identify young stars via their emission lines, and to map the gas distribution in star-forming regions.  The observations completed nominally.
    1.13 Completed WF/PC-2 8812 (Cycle 9 Internal Monitor)
        The WF/PC-2 was used to obtain routine internal monitors for WFPC2 in order to monitor the health of the cameras.  A variety of internal exposures are obtained in order to provide a monitor of the integrity of the CCD camera electronics in both bays {gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows.  There were no reported problems.
    1.14 Completed STIS/CCD 8664 (Structural Measurement of Globular Clusters in M31 and NGC 5128: Stalking the Fundamental Plane)
        The Space Telescope Imaging Spectrograph (CCD) was used to observe in the snapshot mode to image a wide selection of individual globular clusters in two other large galaxies {M31 and NGC 5128} for measurement of their structural parameters {r_c, c, central surface brightness}.  We will use these to compute their binding energies and define the FP in these two galaxies. Comparison with the Milky Way will then give us powerful new information on just how “universal” the cluster formation process was in the early protogalaxies.  The observations completed with no reported problems.
    1.15 Completed Two Sets of STIS/MA2 8843 (Cycle 9 MAMA Dark Measurements)
        The Space Telescope Imaging Spectrograph (MA2) was used to perform the routine monitoring of the MAMA detector dark noise.  The proposal completed nominally.
    1.16 Completed STIS/CCD 8258 (A Search for Kuiper Belt Object Satellites)
        The Space Telescope Imaging Spectrograph (CCD) was used to look for Kuiper belt objects which may have been caused by the large number of collisions thought to have taken place in the primordial Kuiper belt similar to the binary-forming collisions to that which formed the Pluto — Charon binary.  There were no reported anomalies.
    1.17 Completed STIS/CCD 8659 (High Resolution Spectrum of the Venus Lyman-Alpha Line Profile)
        The Space Telescope Imaging Spectrograph (CCD) was used to record a single high spectral resolution observation of the Venus Lyman-alpha line, while HST is within Earth shadow and Venus is at 47.1 degrees solar elongation, with a supporting observation of the Lyman-alpha geocorona outside the exclusion zone {50 degrees}.  The proposal completed with no reported anomalous activity.
    1.18 Completed STIS/CCD 8260 (Searching for the Hydrogen Reionization Edge of the Universe at 5HST)
        The Space Telescope Imaging Spectrograph (CCD) was used to make observations of 15 extreme helium stars (EHEs_ which, together with IUE data, will give a 20-year baseline of ultraviolet spectrophotometry.  EHEs are luminous stellar remnants evolving rapidly to become white
dwarfs.  They represent an important stage in the evolution of at least some low-mass stars, and are closely related to the R Coronae Borealis variables.  Models do not agree about their origin, nor about what fraction of normal stars pass through this phase, in which the stars have been completely stripped of their outer layers.  The models do predict that EHEs are contracting and provide rate predictions and evolutionary
lifetimes.  The observations completed with no reported problems.
    1.19 Completed STIS/CCD 8603 (Secular Changes In The Temperatures And Radii Of Extreme Helium Stars)
        The Space Telescope Imaging Spectrograph (CCD) was used to observe one of 36 parallel orbits {4–5 fields of 5–8 orbits each} to constrain the H Lyman-edge in emission that marks the transition from a neutral to a fully ionized IGM at a predicted zion~eq5–15.  This edge is due to recombination from the H Lyman series and Lyman continuum, and can be used to constrain zion, one of the most important unknown quantities in large scale structure and cosmology.  The proposal completed nominally.
    2.1 Guide Star Acquisitions:
      Scheduled Acquisitions: 13
                Successful: 13
        As described in HSTAR 8004, the acquisition at 348/025925Z defaulted to fine lock backup on FGS-1 only when the scan step limit was exceeded on FGS-3.  The following re-acquisition was performed
nominally.  Three proposals, all occurring during the period of the next report may have been affected: FGS 8831, STIS 8562, and WF/PC-2 8602.     Scheduled Re-acquisitions:  1
                Successful:  1
    2.2 FHST Updates:
                  Scheduled: 26
                Successful: 26
    2.3 Operations Notes:
        Using ROP SR-1A, the SSR EDAC error counter was cleared four times.
        Continuation of normal science observations and calibrations.

SpaceRef staff editor.