NASA Hubble Space Telescope Daily Report #4840

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT #4840

PERIOD COVERED: 5am April 23 – 5am April 24, 2009 (DOY
113/0900z-114/0900z)

OBSERVATIONS SCHEDULED

FGS 11788
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 11943
Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries
among some of the most massive, least massive, and oldest stars in our
part of the Galaxy. FGS allows us to spatially resolve binary systems
that are too faint for ground-based, speckle or optical long baseline
interferometry, and too close to resolve with AO. We propose a
SNAP-style program of single orbit FGS TRANS mode observations of very
massive stars in the cluster NGC 3603, luminous blue variables, nearby
low mass main sequence stars, cool subdwarf stars, and white dwarfs.
These observations will help us to (1) identify systems suitable for
follow up studies for mass determination, (2) study the role of
binaries in stellar birth and in advanced evolutionary states, (3)
explore the fundamental properties of stars near the main
sequence-brown dwarf boundary, (4) understand the role of binaries for
X-ray bright systems, (5) find binaries among ancient and nearby
subdwarf stars, and (6) help calibrate the white dwarf mass – radius
relation.

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 11316
HST Cycle 16 & Pre-SM4 Optical Monitor

This is a continuation of the Cycle 15 & pre-SM4 Optical Monitor,
11020. Please see that proposal for a more complete description of the
observing strategy. The 6 visits comprising this proposal observe two
single standard stars with WFPC2/PC in order to establish overall OTA
focal length for the purposes of focus maintenance. The goal of this
monitoring before SM4 is to establish a best estimate of the OTA focus
entering SMOV.

WFPC2 11979
WFPC2 Imaging of Fomalhaut b: Determining its Orbit and Testing for
H-alpha Emission

Fomalhaut is a bright nearby star that harbors a belt of dusty
material with a morphology that has been used to predict the presence
of a shepherding planet. With ACS/HRC coronagraphy, we have achieved
the direct detection of a planet candidate (Fomalhaut b) in F606W and
F814W. The planet candidate lies 18 AU interior to the dust belt and
we detect counterclockwise orbital motion in two epochs of
observations (2004 and 2006). Fomalhaut b has mass no greater than
three Jupiter masses based on an analysis of its luminosity, including
non-detections at infrared wavelengths, and the dynamical argument
that a significantly more massive object would disrupt the dust belt.
Variability at optical wavelengths and the brightness in the F606W
passband suggest additional sources of luminosity such as starlight
reflected from a circumplanetary ring system. A second possibility
that has been invoked for substellar objects is a significant
contribution of H-alpha emission. Here we propose follow-up WFPC2
observations to test the possibility that the F606W flux is
contaminated by H-alpha emission. We demonstrate that the detection of
Fomalhaut b using WFPC2 is feasible using roll deconvolution.
Furthermore, a detection of Fomalhaut b in 2009 will provide a crucial
third epoch for astrometry. With the existing two epochs of data, the
orbit of Fomalhaut b cannot be determined uniquely. The third epoch
will be used to test the prediction of apsidal alignment and more
accurately determine the dynamical mass of Fomalhaut b. If apsidal
mis-alignment is found between the planet and the belt, this result
would point to the existence of still other planets lurking unseen in
the Fomalhaut system.

WFPC2 11983
An Imaging Survey of Protoplanetary Disks and Brown Dwarfs in the
Chamaeleon I Region

We propose to carry out a HST/WFPC2 survey of young brown dwarfs,
Class I and Class II sources in the Chamaelon I region, one of the
best-studied star-forming regions, in order to investigate the link
between disk evolution and the formation of substellar-mass objects.
We will use deep broad-band imaging in the I and z-equivalent HST
bands to unveil the unknown population of substellar binary
companions, down to a few Jupiter masses for separations of a few tens
of AU. We will also perform narrow-band imaging to directly detect
accreting circumstellar disks and jets around brown dwarfs, Class-I
and class-II objects. Chamaelon I is nearly coeaval of Orion (~1-2Myr)
but at ~1/3 its distance, allowing 3x higher resolution and 10x more
flux for comparable objects. Unlike Orion, low-mass objects and
protoplanetary disks in Chamaeleon I have been extensively studied
with Spitzer, but not yet with the HST. The Chamaeleon I region is an
ideal HST target, as it lies in the CVZ of the HST and therefore it is
easily accessible any time of the year with long orbits.

WFPC2 11987
The Recent Star Formation History of SINGS Galaxies

The Spitzer Legacy project SINGS provided a unique view of the current
state of star formation and dust in a sample of galaxies of all Hubble
types. This multi-wavelength view allowed the team to create current
star formation diagnostics that are independent of the dust content
and increased our understanding of the dust in galaxies. Even so,
using the SINGS data alone we can only make rough estimates of the
recent star formation history of these galaxies. The lack of U-band
observations means that it is impossible to estimate the ages of young
clusters. In addition, the low resolution of the Spitzer and
ground-based observations means that what appear to be individual
Spitzer sources can actually be composed of many individual clusters
with varying ages. In this proposal we plan to address this missing
area in SINGS by obtaining high-resolution WFPC2 UBVI observations to
accurately find and determine the ages of the young stellar clusters
in a subset of the SINGS galaxies. These observations will greatly
enhance the legacy value of the SINGS observations while also directly
answering questions pertaining to star formation in galaxies.

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.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

11781 – GSAcq(1,2,1) failed due to search radius limit exceed on FGS1
@ 114/114/07:53:22z.

Observations Affected: WFPC 49-50, Proposal ID# 11113

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSAcq 09 08
FGS REAcq 05 05
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)