HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT #4912
PERIOD
COVERED: 5am August 18 - 5am August 19, 2009 (DOY 230/09:00z-231/09:00z)
OBSERVATIONS
SCHEDULED
ACS/WFC3
11465
ACS
CCD Monitoring and Calibration for WFC3
This
program is a smaller version of our routine CCD monitoring program,
designed
to run throughout SMOV, after which our regular Cycle 17 CAL
proposal
will begin. This program obtains the bias and dark frames
needed
to generate reference files for calibrating science data, and
allows
us to monitor detector noise and the growth of hot pixels.
NIC2/WFC3/IR
11548
NICMOS
Imaging of Protostars in the Orion A Cloud: The Role of
Environment
in Star Formation
We
propose NICMOS observations of a sample of 252 protostars identified
in
the Orion A cloud with the Spitzer Space Telescope. These
observations
will image the scattered light escaping the protostellar
envelopes,
providing information on the shapes of outflow cavities, the
inclinations
of the protostars, and the overall morphologies of the
envelopes.
In addition, we ask for Spitzer time to obtain 55-95 micron
spectra
of 75 of the protostars. Combining these new data with existing
3.6
to 70 micron photometry and forthcoming 5-40 micron spectra measured
with
the Spitzer Space Telescope, we will determine the physical
properties
of the protostars such as envelope density, luminosity,
infall
rate, and outflow cavity opening angle. By examining how these
properties
vary with stellar density (i.e. clusters vs groups vs
isolation)
and the properties of the surrounding molecular cloud; we can
directly
measure how the surrounding environment influences protostellar
evolution,
and consequently, the formation of stars and planetary
systems.
Ultimately, this data will guide the development of a theory of
protostellar
evolution.
STIS/CCD
11567
Boron
Abundances in Rapidly Rotating Early-B Stars
Models
of rotation in early-B stars predict that rotationally driven
mixing
should deplete surface boron abundances during the main-sequence
lifetime
of many stars. However, recent work has shown that many boron
depleted
stars are intrinsically slow rotators for which models predict
no
depletion should have occurred, while observations of nitrogen in
some
more rapidly rotating stars show less mixing than the models
predict.
Boron can provide unique information on the earliest stages of
mixing
in B stars, but previous surveys have been biased towards
narrow-lined
stars because of the difficulty in measuring boron
abundances
in rapidly rotating stars. The two targets observed as part of
our
Cycle 13 SNAP program 10175, just before STIS failed, demonstrate
that
it is possible to make useful boron abundance measurements for
early-B
stars with Vsin(i) above 100 km/s. We propose to extend that
survey
to a large enough sample of stars to allow statistically
significant
tests of models of rotational mixing in early-B stars.
STIS/CCD
11612
Eta
Carinae's Continuing Instability and Recovery - The 2009 Event
Eta
Carinae is the only really observable example of structural recovery
from
a massive giant eruption, a "supernova imposter' event. Moreover it
is
the only well-observed star above 100 Msun, and its
5.5-year-recurrent
spectroscopic events provide extraordinary clues to
its
surface instability. This truly unique combination of attributes
makes
it valuable for understanding the most massive stars. A fresh
development
arose a few years ago: the star has brightened much faster
than
before, and appears to have entered a rapid stage in its
post-eruption
recovery.
A
spectroscopic event will occur at 2009.0, soon after the planned HST
servicing
mission. Because of the recent secular trend, this event is
expected
to differ from its well- observed 2003.5 predecessor. The
differences
will be very important, because they offer clues to
very-massive-star
structural instabilities that can't be observed in any
other
known way.
Some
of the needed observations require HST's high spatial resolution
and
UV coverage. We propose an efficient, well-chosen set of STIS and
ACS
observations around the critical time. If the servicing mission is
too
late for the event, then a subset of the observations will still be
merited.
STIS/CCD
11844
CCD
Dark Monitor Part 1
Monitor
the darks for the STIS CCD.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
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
11852
STIS
CCD Spectroscopic Flats C17
Obtain
pixel-to-pixel lamp flat fields for the STIS CCD in spectroscopic
mode.
STIS20
11402
STIS-20
NUV MAMA Dark Monitor
The
STIS NUV-MAMA dark current is dominated by a phosphorescent glow
from
the detector window. Meta-stable states in this window are
populated
by cosmic ray impacts, which, days later, can be thermally
excited
to an unstable state from which they decay, emitting a UV
photon.
The equilibrium population of these meta-stable states is larger
at
lower temperatures; so warming up the detector from its cold safing
will
lead to a large, but temporary, increase in the dark current.
To
monitor the decay of this glow, and to determine the equilibrium dark
current
for Cycle 17, four 1380s NUV-MAMA ACCUM mode darks should be
taken
each week during the SMOV period. Once the observed dark current
has
reached an approximate equilibrium with the mean detector
temperature,
the frequency of this monitor can be reduced to one pair of
darks
per week.
WFC3
11428
D2
Calibration Lamp Test
This
proposal verifies the health and performance of the calsystem
deuterium
lamp and assesses the status of the major UV filters by taking
a
full set of internal flatfields. A total of three nominal and one
short
exposure are obtained for each filter in order to establish an
initial
baseline of flatfield data as well as to confirm lamp
repeatability
and provide a contamination check. Additional iterations
of
D2 internal flatfields will be taken as part of WFC-19, UVIS Internal
Flats
(proposal 11432).
This
proposal corresponds to SMOV ID WFC3-15. It should not be run until
after
the successful completion of WFC-06, the UVIS detector functional
test
(proposal 11419) and WFC-11, the initial UVIS alignment (proposal
11424).
WFC3/ACS/IR
11590
Observing
the IR Catastrophe in a Deflagration Type Ia Supernova
Our
lack of understanding of Type Ia supernova (SN Ia) explosions limits
our
confidence in their use for cosmology. While there is broad
agreement
that these objects represent the explosions of white dwarfs,
the
details of the explosion mechanism are not well- understood.
Recently,
we have identified an internally homogeneous subclass of SNe
Ia
whose photometric and spectroscopic peculiarities make them quite
distinct
from normal SNe Ia. Models suggest we may be seeing the result
of
an explosion with a subsonic burning front, called a deflagration. We
propose
to test SN Ia models by obtaining late-time photometry for SN
2008A,
a recent, nearby example of this subclass, using ACS and WFC3 on
HST.
We will accurately measure the late-time photometric decline rate
and
spectral energy distribution (SED). These observations will allow us
to
test whether the ejecta contain the large amount of oxygen predicted
by
certain models. We also aim to detect major evolution of the SED
expected
due to the "IR catastrophe", a change in the dominant cooling
mechanism
in the ejecta, as generically predicted by models but only
hinted
at by current observations.
WFC3/ACS/UVI
11877
HST
Cycle 17 and Post-SM4 Optical Monitor
This
program is the cycle 17 implementation of the HST Optical
Monitoring
Program.
The
36 orbits comprising this proposal will utilize ACS (Wide Field
channel)
and WFC3 (UVIS channel) to observe stellar cluster members in
parallel
with multiple exposures over an orbit. Phase retrieval
performed
on the PSF in each image will be used to measure primarily
focus,
with the ability to explore apparent coma, and astigmatism
changes
in WFC3. The goals of this program are to: 1) monitor the
overall
OTA focal length for the purposes of maintaining focus within
science
tolerances 2) gain experience with the relative effectiveness of
phase
retrieval on WFC3/UVIS PSFs 3) determine focus offset between the
imagers
and identify any SI-specific focus behavior and dependencies
If
need is determined, future visits will be modified to interleave
WFC3/IR
channel and STIS/CCD focii measurements.
WFC3/IR
11915
IR
Internal Flat Fields
This
program is the same as 11433 (SMOV) and depends on the completion
of
the IR initial alignment (program 11425). This version contains three
instances
of 37 internal orbits; to be scheduled early, middle, and near
the
end of Cycle 17, in order to use the entire 110-orbit allocation.
In
this test, we will study the stability and structure of the IR
channel
flat field images through all filter elements in the WFC3-IR
channel.
Flats will be monitored, i.e. to capture any temporal trends in
the
flat fields, and delta flats produced. High signal observations will
provide
a map of the pixel-to-pixel flat field structure, as well as
identify
the positions of any dust particles.
WFC3/UVI
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 (11909), will be
used
to generate the necessary superbias and superdark reference files
for
the calibration pipeline (CDBS).
WFC3/UVI
11907
UVIS
Cycle 17 Contamination Monitor
The
UV throughput of WFC3 during Cycle 17 is monitored via weekly
standard
star observations in a subset of key filters covering 200-600nm
and
F606W, F814W as controls on the red end. The data will provide a
measure
of throughput levels as a function of time and wavelength,
allowing
for detection of the presence of possible contaminants.
WFC3/UVI
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:
18686-1
- Recover NICMOS to SAA Operate @ 230/16:18z
18690-0
- Execute ROP NS-12 to Reset STIS Error Counter @ 231/01:15z
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
06
06
FGS
REAcq
10
10
OBAD
with Maneuver
06
06
SIGNIFICANT
EVENTS:
Flash
Report: NICMOS in SAA Operate
At
230/16:18 z, NICMOS successfully completed the transition from safe
to
SAA Operate via Ops Request 18686. At 17:59z, the three Focal Plane
Assembly
(FPA) temperature sensors were enabled via Ops Request 18689.