HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4691
PERIOD COVERED: 5am September 8 - 5am September 9, 2008
(DOY 252/0900z-253/0900z)
OBSERVATIONS SCHEDULED
NIC1/NIC2 11818
NICMOS Confirmation of an Extrasolar Panet Candidate
Directly Detected
with ACS
With ACS/HRC coronagraphy, we have achieved the direct
detection of a
planet candidate in F606W and F814W around a bright nearby
star with a
debris belt. The planet candidate lies 18 astronomical
units interior to
the dust belt and we detect counterclockwise orbital
motion in
observations separated by 1.75 years. The candidate has
mass no greater
than three Jupiter masses based on an analysis of its
luminosity and the
dynamical argument that a significantly more massive
object would
disrupt the dust belt. Using recent model predictions for
100-300 Myr
old planetary atmospheres, the planet candidate has a
temperature of
~400 K and a mass 1.6 - 3.4 M_J. Variability at optical
wavelengths
suggests additional sources of luminosity such as H-alpha
emission or
the episodic accretion of cometary material. A key
surprise is that the
planet candidate is NOT detected in Keck adaptive optics
observations at
1.6 microns. Two model atmospheres predict a flux a few
times greater
than our detection limit, though the model predictions
disagree with
each other by a factor of five due to theoretical
uncertainty in the
strength of CH4 vibrational bands. These models predict
the strongest
emission centered on the F110W passband of NICMOS such
that the F814W -
F110W color will be red. Here we propose follow-up NICMOS
observations
to verify that the emission observed in F814W is due to
the emergent
flux from passive cooling of the planet, as opposed to
other
explanations, such as reflected light from a Saturn analog
with a
circumplanetary debris disk that would produce a bluer
F814W - F110W
color. Additional deep images in and and out of the 1.14
micron water
trough using NIC1 narrowband filters will test whether or
not the
emission is produced from the passive cooling of a young
massive planet.
NIC1/NIC2/NIC3 11820
NICMOS Post-SAA Calibration - CR Persistence Part 7
Internals for CR persistence
NIC2 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.
WFPC2 11113
Binaries in the Kuiper Belt: Probes of Solar System
Formation and
Evolution
The discovery of binaries in the Kuiper Belt and related
small body
populations is powering a revolutionary step forward in
the study of
this remote region. Three quarters of the known binaries
in the Kuiper
Belt have been discovered with HST, most by our snapshot
surveys. The
statistics derived from this work are beginning to yield
surprising and
unexpected results. We have found a strong concentration
of binaries
among low-inclination Classicals, a possible size cutoff
to binaries
among the Centaurs, an apparent preference for nearly
equal mass
binaries, and a strong increase in the number of binaries
at small
separations. We propose to continue this successful
program in Cycle 16;
we expect to discover at least 13 new binary systems,
targeted to
subgroups where these discoveries can have the greatest
impact.
WFPC2 11130
AGNs with Intermediate-mass Black Holes: Testing the Black
Hole-Bulge
Paradigm, Part II
The recent progress in the study of central black holes in
galactic
nuclei has led to a general consensus that supermassive
{10^6-10^9 solar
mass} black holes are closely connected with the formation
and
evolutionary history of large galaxies, especially their
bulge
component. Two outstanding issues, however, remain
unresolved. Can
central black holes form in the absence of a bulge? And
does the mass
function of central black holes extend below 10^6 solar
masses?
Intermediate-mass black holes {<10^6 solar masses}, if
they exist, may
offer important clues to the nature of the seeds of
supermassive black
holes. Using the SDSS, our group has successfully
uncovered a new
population of AGNs with intermediate-mass black holes that
reside in
low-luminosity galaxies. However, very little is known
about the
detailed morphologies or structural parameters of the host
galaxies
themselves, including the crucial question of whether they
have bulges
or not. Surprisingly, the majority of the targets of our
Cycle 14 pilot
program have structural properties similar to dwarf
elliptical galaxies.
The statistics from this initial study, however, are
really too sparse
to reach definitive conclusions on this important new
class of black
holes. We wish to extend this study to a larger sample, by
using the
Snapshot mode to obtain WFPC2 F814W images from a parent
sample of 175
AGNs with intermediate- mass black holes selected from our
final SDSS
search. We are particularly keen to determine whether the
hosts contain
bulges, and if so, how the fundamental plane properties of
the host
depend on the mass of their central black holes. We will
also
investigate the environment of this unique class of AGNs.
WFPC2 11218
Snapshot Survey for Planetary Nebulae in Globular Clusters
of the Local
Group
Planetary nebulae {PNe} in globular clusters {GCs} raise a
number of
interesting issues related to stellar and galactic
evolution. The number
of PNe known in Milky Way GCs, 4, is surprisingly low if
one assumes
that all stars pass through a PN stage. However, it is
likely that the
remnants of stars now evolving in Galactic GCs leave the
AGB so slowly
that any ejected nebula dissipates long before the star
becomes hot
enough to ionize it. Thus there should not be ANY PNe in
Milky Way
GCs--but there are four! It has been suggested that these
PNe are the
result of mergers of binary stars within GCs, i.e., that
they are
descendants of blue stragglers. The frequency of occurrence
of PNe in
external galaxies poses more questions, because it shows a
range of
almost an order of magnitude. I propose a Snapshot survey
aimed at
discovering PNe in the GC systems of Local Group galaxies
more distant
than the Magellanic Clouds. These clusters, some of which
may be much
younger than their counterparts in the Milky Way, might
contain many
more PNe than those of our own galaxy. I will use the
standard technique
of emission-line and continuum imaging, which easily
discloses PNe.
WFPC2 11291
Following Eta Carinae's Change of State
Eta Carinae is now known to be undergoing some unusually
rapid changes
on a timescale of several years. They are probably
essential for
modeling the star's long-term recovery from its Giant
Eruption 160 years
ago -- the prototype "supernova impostor" event.
Since high spatial
resolution is needed to isolate the central star, and the
present state
will probably not recur in the future, it is important to
obtain HST
data during the next two years. We propose a cost-
effective set of ACS
observations with three goals: {1} to obtain a continuing
record of the
star's rapid UV and visual brightening; {2} to lengthen
the temporal
baseline of ACS images enough to settle an important
question concerning
ejecta ages; and {3} to extend the record of morphological
changes in
the inner ejecta past the midpoint of eta Car's 5.5-year
cycle.
WFPC2 11302
WFPC2 CYCLE 16 Standard Darks - Part III
This dark calibration program obtains 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.
WFPC2 11793
WFPC2 Cycle 16 Internal Monitor
This calibration proposal is the Cycle 15 routine internal
monitor for
WFPC2, to be run weekly 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 (both
gain 7 and
gain 15 -- to test stability of gains and bias levels), a
test for
quantum efficiency in the CCDs, and a monitor for possible
buildup of
contaminants on the CCD windows. These also provide raw data
for
generating annual super-bias reference files for the
calibration
pipeline.
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
13
13
FGS
REacq
01
01
OBAD with Maneuver
28
28
SIGNIFICANT EVENTS: (None)