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Daily Report #4403



 
 
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Old July 13th 07, 03:12 PM posted to sci.astro.hubble
Pataro, Pete
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Posts: 33
Default Daily Report #4403

Notice: Due to the conversion of some ACS WFC or HRC observations into
WFPC2, or NICMOS observations after the loss of ACS CCD science
capability in January, there may be an occasional discrepancy between
a proposal's listed (and correct) instrument usage and the abstract
that follows it.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4403

PERIOD COVERED: UT July 12, 2007 (DOY 193)

OBSERVATIONS SCHEDULED

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary
system architecture as yet untested by direct observation for main
sequence stars other than the Sun. To provide such a test, we propose
to carry out FGS astrometric studies on four stars hosting seven
companions. Our understanding of the planet formation process will
grow as we match not only system architecture, but formed planet mass
and true distance from the primary with host star characteristics for
a wide variety of host stars and exoplanet masses. We propose that a
series of FGS astrometric observations with demonstrated 1 millisecond
of arc per-observation precision can establish the degree of
coplanarity and component true masses for four extrasolar systems: HD
202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu
Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}. In
each case the companion is identified as such by assuming that the
minimum mass is the actual mass. For the last target, a known stellar
binary system, the companion orbit is stable only if coplanar with the
AB binary orbit.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic
O Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long
term spectroscopic and high angular resolution observations to
determine their masses and distances. The results will also be
important for the interpretation of the spectra of suspected and newly
identified binary and multiple systems.

NIC3 11080

Exploring the Scaling Laws of Star Formation

As a variety of surveys of the local and distant Universe are
approaching a full census of galaxy populations, our attention needs
to turn towards understanding and quantifying the physical mechanisms
that trigger and regulate the large-scale star formation rates {SFRs}
in galaxies.

WFPC2 10818

Very Young Globular Clusters in M31 ?

We propose to use HST's unique high spatial resolution imaging
capabilities to conclusively confirm or refute the presence of alleged
very young globular clusters in M31. Such young globular clusters with
ages 3 Gyr are not present in our galaxy, and, if real, would lead
to a striking difference in the age distribution of the GCs between
M31 and the Millky Way. If the apparent presence of very young
globular clusters in M31 is confirmed through our proposed ACS imaging
{now WFPC2 imaging} with HST, this would suggest major differences in
the history of assembly of the two galaxies, with probable substantial
late accretion into M31 which did not occur in our own galaxy.

WFPC2 10902

The Nearest Luminous Blue Compact Galaxies: A Window on Galaxy
Formation

As we move to intermediate and high redshifts, Luminous Blue Compact
Galaxies {LBCGs} become increasingly common. The nearest LBCGs, with
their violent starbursts and rich populations of super star clusters
{SSCs} and globular clusters {GCs}, thus provide ideal laboratories
for studying galaxy evolution. Many LBCGs appear to be involved in
mergers between dwarf galaxies, triggering their starbursts. The
starburst regions in LBCGs consist of numerous young star clusters,
whose populations are both easily measurable with HST and easily
modelled. Studying cluster populations provides a powerful probe of
the starburst and merger history which is possible neither for closer
objects {of which there are too few} or for those at high redshift
{which are too far away}. We have previously studied the closest LBCG
with WFPC2 and found hundreds of bright compact SSCs and GCs. In
particular, we found a population of intermediate-age {~2 Gyr} GCs,
indicating a past event of massive cluster formation. We now propose a
multi-wavelength study of the three other LBCGs with the highest known
number of SSCs. The extinction is small in these galaxies and age
estimates robust. The age distribution of GCs and SSCs will be used to
study the past evolution of the galaxies. For each LBCG, we will map
its cluster formation history, unveiling its merger and starburst
history, and thereby shed light on some of the processes involved in
galaxy evolution at high redshift.

WFPC2 11079

Treasury Imaging of Star Forming Regions in the Local Group:
Complementing the GALEX and NOAO Surveys

We propose to use WFPC2 to image the most interesting star-forming
regions in the Local Group galaxies, to resolve their young stellar
populations. We will use a set of filters including F170W, which is
critical to detect and characterize the most massive stars, to whose
hot temperatures colors at longer wavelengths are not sensitive.
WFPC2's field of view ideally matches the typical size of the
star-forming regions, and its spatial resolution allows us to measure
indvidual stars, given the proximity of these galaxies. The resulting
H-R diagrams will enable studies of star- formation properties in
these regions, which cover largely differing metallicities {a factor
of 17, compared to the factor of 4 explored so far} and
characteristics. The results will further our understanding of the
star-formation process, of the interplay between massive stars and
environment, the properties of dust, and will provide the key to
interpret integrated measurements of star-formation indicators {UV,
IR, Halpha} available for several hundreds more distant galaxies. Our
recent deep surveys of these galaxies with GALEX {FUV, NUV} and
ground-based imaging {UBVRI, Halpha, [OIII] and [SII]} provided the
identification of the most relevant SF sites. In addition to our
scientific analysis, we will provide catalogs of HST photometry in 6
bands, matched corollary ground-based data, and UV, Halpha and IR
integrated measurements of the associations, for comparison of
integrated star-formation indices to the resolved populations. We
envisage an EPO component.

WFPC2 11178

Probing Solar System History with Orbits, Masses, and Colors of
Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens
a window into dynamical conditions in the protoplanetary disk where
they formed as well as the history of subsequent events which sculpted
the outer Solar System and emplaced them onto their present day
heliocentric orbits. To date, at least 47 TNBs have been discovered,
but only about a dozen have had their mutual orbits and separate
colors determined, frustrating their use to investigate numerous
important scientific questions. The current shortage of data
especially cripples scientific investigations requiring statistical
comparisons among the ensemble characteristics. We propose to obtain
sufficient astrometry and photometry of 23 TNBs to compute their
mutual orbits and system masses and to determine separate primary and
secondary colors, roughly tripling the sample for which this
information is known, as well as extending it to include systems of
two near-equal size bodies. To make the most efficient possible use of
HST, we will use a Monte Carlo technique to optimally schedule our
observations.

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)

***************************** SCHEDULED***** SUCCESSFUL

FGS GSacq******************** 10****************** 10
FGS REacq********************* 4******************* 4
OBAD with Maneuver*********** 28****************** 28

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS: (None)


 




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