Status Report

NASA Hubble Space Telescope Daily Report #4964

By SpaceRef Editor
November 5, 2009
Filed under , ,


Continuing to Collect World Class Science

PERIOD COVERED: 5am November 2 – 5am November 3, 2009 (DOY 306/10:00z-307/10:00z)


ACS/WFC3 11879

CCD Daily Monitor (Part 1)

This program comprises basic tests for measuring the read noise and dark current of the ACS WFC and for tracking the growth of hot pixels. The recorded frames are used to create bias and dark reference images for science data reduction and calibration. This program will be executed four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To facilitate scheduling, this program is split into three proposals. This proposal covers 352 orbits (22 weeks) from 31 August 2009 to 31 January 2010.

COS/FUV 11895

FUV Detector Dark Monitor

The purpose of this proposal is to monitor the FUV detector dark rate by taking long science exposures without illuminating the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA. Dependence of dark rate as function of time will also be tracked.

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.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate by taking long science exposures with no light on the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA. Dependence of dark rate as function of time will also be tracked.

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.

NIC2/WFC3/IR 11548

Infrared Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation

We propose NICMOS and WFC3/IR 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 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 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.

STIS 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.


Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields The first generations of galaxies were assembled around redshifts z~7-10+, just 500-800 Myr after recombination, in the heart of the reionization of the universe. We know very little about galaxies in this period. Despite great effort with HST and other telescopes, less than ~15 galaxies have been reliably detected so far at z>7, contrasting with the ~1000 galaxies detected to date at z~6, just 200-400 Myr later, near the end of the reionization epoch. WFC3 IR can dramatically change this situation, enabling derivation of the galaxy luminosity function and its shape at z~7-8 to well below L*, measurement of the UV luminosity density at z~7-8 and z~8-9, and estimates of the contribution of galaxies to reionization at these epochs, as well as characterization of their properties (sizes, structure, colors). A quantitative leap in our understanding of early galaxies, and the timescales of their buildup, requires a total sample of ~100 galaxies at z~7-8 to ~29 AB mag. We can achieve this with 192 WFC3 IR orbits on three disjoint fields (minimizing cosmic variance): the HUDF and the two nearby deep fields of the HUDF05. Our program uses three WFC3 IR filters, and leverages over 600 orbits of existing ACS data, to identify, with low contamination, a large sample of over 100 objects at z~7-8, a very useful sample of ~23 at z~8-9, and limits at z~10. By careful placement of the WFC3 IR and parallel ACS pointings, we also enhance the optical ACS imaging on the HUDF and a HUDF05 field. We stress (1) the need to go deep, which is paramount to define L*, the shape, and the slope alpha of the luminosity function (LF) at these high redshifts; and (2) the far superior performance of our strategy, compared with the use of strong lensing clusters, in detecting significant samples of faint z~7-8 galaxies to derive their luminosity function and UV ionizing flux. Our recent z~7.4 NICMOS results show that wide-area IR surveys, even of GOODS-like depth, simply do not reach faint enough at z~7-9 to meet the LF and UV flux objectives. In the spirit of the HDF and the HUDF, we will waive any proprietary period, and will also deliver the reduced data to STScI. The proposed data will provide a Legacy resource of great value for a wide range of archival science investigations of galaxies at redshifts z~2-9. The data are likely to remain the deepest IR/optical images until JWST is launched, and will provide sources for spectroscopic followup by JWST, ALMA and EVLA.

WFC3/UV 12045

Evolution of the 2009 Single Impact on Jupiter

The 19 July 2009 impact on Jupiter captured worldwide attention, and sparked a highly successful WFC3 imaging program during SMOV, with the last Hubble image acquired on 8 August. Continuing ground-based observations have revealed significant differences between this event and the Shoemaker-Levy 9 impacts in 1994: a single impact event offers a chance to study the longer-term evolution of the impact debris field without confusion due to overlapping aerosol debris clouds, and this debris field evolved more slowly than the SL9 sites. Initial analysis of our first data set reveals possible curved streamlines that correspond to no known tropospheric vortex. To constrain the stratospheric velocity field traced by the impact-generated aerosols, we request 10-hour separated data (a temporal sampling rate which we could not obtain during SMOV) that are crucial for tracking coherent albedo features. We also requested (but were not granted) a single orbit of high-resolution near-infrared images. These data would have provided the sharpest visible and near-infrared images of the site, providing context for the ongoing worldwide campaign of lower-resolution ground-based observations.

WFC3/UV 11657

The Population of Compact Planetary Nebulae in the Galactic Disk

We propose to secure narrow- and broad-band images of compact planetary nebulae (PNe) in the Galactic Disk to study the missing link of the early phases of post-AGB evolution. Ejected AGB envelopes become PNe when the gas is ionized. PNe expand, and, when large enough, can be studied in detail from the ground. In the interim, only the HST capabilities can resolve their size, morphology, and central stars. Our proposed observations will be the basis for a systematic study of the onset of morphology. Dust properties of the proposed targets will be available through approved Spitzer/IRS spectra, and so will the abundances of the alpha- elements. We will be able thus to explore the interconnection of morphology, dust grains, stellar evolution, and populations. The target selection is suitable to explore the nebular and stellar properties across the galactic disk, and to set constraints on the galactic evolutionary models through the analysis of metallicity and population gradients.

WFC3/UV 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/UV/IR 11644

A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into the Formation of the Outer Solar System

The eight planets overwhelmingly dominate the solar system by mass, but their small numbers, coupled with their stochastic pasts, make it impossible to construct a unique formation history from the dynamical or compositional characteristics of them alone. In contrast, the huge numbers of small bodies scattered throughout and even beyond the planets, while insignificant by mass, provide an almost unlimited number of probes of the statistical conditions, history, and interactions in the solar system. To date, attempts to understand the formation and evolution of the Kuiper Belt have largely been dynamical simulations where a hypothesized starting condition is evolved under the gravitational influence of the early giant planets and an attempt is made to reproduce the current observed populations. With little compositional information known for the real Kuiper Belt, the test particles in the simulation are free to have any formation location and history as long as they end at the correct point. Allowing compositional information to guide and constrain the formation, thermal, and collisional histories of these objects would add an entire new dimension to our understanding of the evolution of the outer solar system. While ground based compositional studies have hit their flux limits already with only a few objects sampled, we propose to exploit the new capabilities of WFC3 to perform the first ever large-scale dynamical-compositional study of Kuiper Belt Objects (KBOs) and their progeny to study the chemical, dynamical, and collisional history of the region of the giant planets. The sensitivity of the WFC3 observations will allow us to go up to two magnitudes deeper than our ground based studies, allowing us the capability of optimally selecting a target list for a large survey rather than simply taking the few objects that can be measured, as we have had to do to date. We have carefully constructed a sample of 120 objects which provides both overall breadth, for a general understanding of these objects, plus a large enough number of objects in the individual dynamical subclass to allow detailed comparison between and within these groups. These objects will likely define the core Kuiper Belt compositional sample for years to come. While we have many specific results anticipated to come from this survey, as with any project where the field is rich, our current knowledge level is low, and a new instrument suddenly appears which can exploit vastly larger segments of the population, the potential for discovery — both anticipated and not — is extraordinary.


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


12063 – GSAcq(1,2,1) scheduled at 306/19:35:51z failed due to scan step limit exceeded on FGS2.

Observation affected WFC3 21 proposal ID# 11657



FGS GSAcq 12 11
FGS REAcq 05 05
OBAD with Maneuver 10 10


SpaceRef staff editor.