HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #4926
PERIOD
COVERED: 5am September 8 - 5am September 9, 2009 (DOY 251/09:00z-252/09:00z)
OBSERVATIONS
SCHEDULED
ACS/SBC
12003
The
Impact Event on Jupiter in 2009
An
image of Jupiter taken on 19 July 2009 at 15 UT showed an anomalous
feature
in the southern hemisphere. The world-wide community responded
with
observations, and the subsequent data strongly suggest that an
impact
occurred during the 8 hours preceding that discovery image. The
Hubble
Space Telescope is the only facility that can provide
high-spatial-resolution
visible images of the impact site, and the only
facility
that can provide UV images that show the impactor's effect on
the
Jovian stratosphere. We request 7 orbits of HST time to characterize
this
rare event. We hope that two orbits can be as soon as is feasible
(Wednesday
or Thursday, 22 or 23 July). We would like a second pair
several
days later, perhaps Saturday. We request another 2 orbits the
following
week. The last, seventh, orbit can be several weeks or a month
later.
COS/FUV
11493
COS
FUV Structural and Thermal Stability
The
goal of this program is to measure OTA-COS pointing jitter or
drifts,
over timescales of minutes to hours. In particular, our
priorities
are to test the level of OSM1 drift, thermal day-night
transitions
and orbital 'breathing'. Pointing-related thermal offsets
with
their related drifts during thermal settling will be overlaid upon
the
signatures of the other components of positional change. Three
different
instrumental configurations/transitions will be tested: NUV
and
FUV spectroscopy, and NUV imaging using Mirror A. All with the PSA.
No
FP-POS motions, nor grating changes will be made during the
spectroscopy
in order to limit the variables contributing to any changes
in
position of the spectra.
ID:
COS 20 (Proposal 11480) & COS 35 (Proposal 11493) This is the FUV
portion
of this experiment. It was initially estimated to be a 3-orbit
program,
but has been extended to 5 orbits in order to improve the
statistics
of our measure of the effect of day-night/breathing.
COS/FUV
11897
FUV
Spectroscopic Sensitivity Monitoring
The
purpose of this proposal is to monitor sensitivity in each FUV
grating
mode to detect any changes due to contamination or other causes.
FGS
11942
Increasing
the Accuracy of HST Astrometry with FGS1R
We
propose to observe six exoplanetary system host stars and two
planetary
nebulae central stars with FGS1R. All objects have been
previously
observed under proposals GO-09233, -09969, -10989, and
-11210.
These observations will significantly extend the time baseline,
permitting
improvements in the determination of proper motion. This
systematic
motion must be removed to get at the perturbation of
interest,
either due to exoplanetary companions or the orbital motion of
the
Earth (parallax). In most cases the perturbation orbits will also
improve.
We improve either companion mass or PN parallax. For one
target,
GJ 876, theoretical dynamical modelers have proposed an
inclination
closer to 50 degrees, while FGS3 measurements indicated an
inclination
closer to 84 degrees. These new data, once combined with our
older
FGS3 data, will permit an independent remeasurement of the
inclination
of the outermost companion, and a re- evaluation of widely
used
dynamical algorithms.
STIS/CCD
11844
CCD
Dark Monitor Part 1
The
purpose of this proposal is to monitor the darks for the STIS CCD.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
The
purpose of this proposal is to monitor the bias in the 1x1, 1x2,
2x1,
and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N
superbiases and track the evolution of hot columns.
STIS/CCD
11849
STIS
CCD Hot Pixel Annealing
This
purpose of this activity is to repair radiation induced hot pixel
damage
to the STIS CCD by warming the CCD to the ambient instrument
temperature
and annealing radiation-damaged pixels.
Radiation
damage creates hot pixels in the STIS CCD Detector. Many of
these
hot pixels can be repaired by warming the CCD from its normal
operating
temperature near - 83 deg. C to the ambient instrument
temperature
(~ +5 deg. C) for several hours. The number of hot pixels
repaired
is a function of annealing temperature. The effectiveness of
the
CCD hot pixel annealing process is assessed by measuring the dark
current
behavior before and after annealing and by searching for any
window
contamination effects.
WFC3/IR
11719
A
Calibration Database for Stellar Models of Asymptotic Giant Branch
Stars
Studies
of galaxy formation and evolution rely increasingly on the
interpretation
and modeling of near-infrared observations. At these
wavelengths,
the brightest stars are intermediate mass asymptotic giant
branch
(AGB) stars. These stars can contribute nearly 50% of the
integrated
luminosity at near infrared and even optical wavelengths,
particularly
for the younger stellar populations characteristic of
high-redshift
galaxies (z>1). AGB stars are also significant sources of
dust
and heavy elements. Accurate modeling of AGB stars is therefore of
the
utmost importance.
The
primary limitation facing current models is the lack of useful
calibration
data. Current models are tuned to match the properties of
the
AGB population in the Magellanic Clouds, and thus have only been
calibrated
in a very narrow range of sub- solar metallicities.
Preliminary
observations already suggest that the models are
overestimating
AGB lifetimes by factors of 2-3 at lower metallicities.
At
higher (solar) metallicities, there are no appropriate observations
for
calibrating the models.
We
propose a WFC3/IR SNAP survey of nearby galaxies to create a large
database
of AGB populations spanning the full range of metallicities and
star
formation histories. Because of their intrinsically red colors and
dusty
circumstellar envelopes, tracking the numbers and bolometric
fluxes
of AGB stars requires the NIR observations we propose here. The
resulting
observations of nearby galaxies with deep ACS imaging offer
the
opportunity to obtain large (100-1000's) complete samples of AGB
stars
at a single distance, in systems with well-constrained star
formation
histories and metallicities.
WFC3/IR/S/C
11929
IR
Dark Current Monitor
Analyses
of ground test data showed that dark current signals are more
reliably
removed from science data using darks taken with the same
exposure
sequences as the science data, than with a single dark current
image
scaled by desired exposure time. Therefore, dark current images
must
be collected using all sample sequences that will be used in
science
observations. These observations will be used to monitor changes
in
the dark current of the WFC3-IR channel on a day-to-day basis, and to
build
calibration dark current ramps for each of the sample sequences to
be
used by GOs in Cycle 17. For each sample sequence/array size
combination,
a median ramp will be created and delivered to the
calibration
database system (CDBS).
WFC3/UVIS
11565
A
Search for Astrometric Companions to Very Low-Mass, Population II
Stars
We
propose to carry out a Snapshot search for astrometric companions in
a
subsample of very low-mass, halo subdwarfs identified within 120
parsecs
of the Sun. These ultra-cool M subdwarfs are local
representatives
of the lowest-mass H burning objects from the Galactic
Population
II. The expected 3-4 astrometric doubles that will be
discovered
will be invaluable in that they will be the first systems
from
which gravitational masses of metal-poor stars at the bottom of the
main
sequence can be directly measured.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
WFC3/UVIS
11908
Cycle
17: UVIS Bowtie Monitor
Ground
testing revealed an intermittent hysteresis type effect in the
UVIS
detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially
found via an unexpected bowtie-shaped feature in flatfield
ratios,
subsequent lab tests on similar e2v devices have since shown
that
it is also present as simply an overall offset across the entire
CCD,
i.e., a QE offset without any discernable pattern. These lab tests
have
further revealed that overexposing the detector to count levels
several
times full well fills the traps and effectively neutralizes the
bowtie.
Each visit in this proposal acquires a set of three 3x3 binned
internal
flatfields: the first unsaturated image will be used to detect
any
bowtie, the second, highly exposed image will neutralize the bowtie
if
it is present, and the final image will allow for verification that
the
bowtie is gone.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
(None)
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
4
4
FGS
REAcq
7
7
OBAD
with Maneuver
3
3
SIGNIFICANT
EVENTS: (None)