Status Report

NASA Hubble Space Telescope Daily Report #4163

By SpaceRef Editor
July 26, 2006
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NASA Hubble Space Telescope Daily Report #4163

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT July 25, 2006 (DOY 206)


ACS/HRC 10800

Kuiper Belt Binaries: Probes of Early Solar System Evolution

Binaries in the Kuiper Belt are a scientific windfall: in them we have relatively fragile test particles which can be used as tracers of the early dynamical evolution of the outer Solar System. We propose to continue a Snapshot program using the ACS/HRC that has a demonstrated discovery potential an order of magnitude higher than the HST observations that have already discovered the majority of known transneptunian binaries. With this continuation we seek to reach the original goals of this project: to accumulate a sufficiently large sample in each of the distinct populations collected in the Kuiper Belt to be able to measure, with statistical significance, how the fraction of binaries varies as a function of their particular dynamical paths into the Kuiper Belt. Today’s Kuiper Belt bears the imprints of the final stages of giant-planet building and migration; binaries may offer some of the best preserved evidence of that long-ago era.

ACS/HRC 10805

ACS Imaging of Uranus’ Atmosphere Near Equinox

Uranus’ 97-degree spin axis inclination results in the largest fractional seasonal variation of solar insolation in the solar system. Uranus is now close to its 7 December 2007 equinox, and we can now see most of the northern hemisphere, which was in darkness when Voyager provided our first detailed view of the planet in 1986. If Uranus’ seasonal response has the large phase shift expected from its long radiative time constant, it should now exhibit nearly maximal hemispheric contrast. Although the long time constant also suggests a small physical response, significant hemispheric asymmetries in cloud structure and dynamics are becoming apparent. We propose a detailed characterization of Uranus’ current response to this forcing with a 10-orbit program consisting of 4 orbits of WFC imaging with narrowband ramp filters and 6 orbits of HRC imaging using both broadband and narrowband filters. Nine narrow-band filters between 0.62 and 0.955 microns will provide vertical sensing depths scanning through the pressure range where the putative methane and deeper H2S clouds might plausibly exist and provide strong constraints on their optical properties and parent gas mixing ratios. The high resolution HRC images will characterize the dynamics of discrete features at the 15-30 hour time scale unavailable from the ground. Short wavelength HRC images will enable a characterization of the stratospheric haze. These observations have unique combinations of spectral range and resolution with needed temporal and spatial resolution not available from groundbased observations.

ACS/WFC 10258

Tracing the Emergence of the Hubble Sequence Among the Most Luminous and Massive Galaxies

There is mounting evidence that the redshift range 1 < z < 2 was an important era when massive galaxies assembled their stellar content and assumed their present--day morphologies. Despite extensive HST imaging surveys, however, there is very little data in the optical rest frame {i.e., observed near--infrared} on the morphologies of the most luminous galaxies at these redshifts. We propose to image a carefully selected set of 20 of the most luminous, K--band selected GOODS galaxies at 1.3 < z < 2, using NICMOS camera 2. This offers diffraction--limited, critically sampled imaging at 1.6 microns to ensure the best angular resolution for comparison to ACS. The galaxies are chosen to span a simple 4--fold parameter space of morphological and spectral type, in order to provide the most information about the variety of massive galaxy properties in this redshift range. We will investigate the emergence of large scale--length disks, stable spiral structure, mature bulges with red stellar populations, central bar structures, the incidence of disturbed morphology, the existence {or lack thereof} of blue ellipticals, and other questions that concern the evolution and maturation of the brightest, largest, and most massive ordinary galaxies in this critical redshift range.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration – CR Persistence Part 5

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non- standard reference files available to users with a USEAFTER date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC2 10849

Imaging Scattered Light from Debris Disks Discovered by the Spitzer Space Telescope around 21 Sun-like Stars

We propose to use the high-contrast capability of the NICMOS coronagraph to image a sample of newly discovered circumstellar disks associated with Sun-like stars. These systems were identified by their strong thermal infrared {IR} emission with the Spitzer Space Telescope as part of the Spitzer Legacy Science program titled “The Formation and Evolution of Planetary Systems” {FEPS, P.I.: M.Meyer}. Modeling of the thermal excess emission from the spectral energy distributions alone cannot distinguish between narrowly confined high-opacity disks and broadly distributed, low-opacity disks. By resolving light scattered by the circumstellar material, our proposed NICMOS observations can break this degeneracy, thus revealing the conditions under which planet formation processes are occuring or have occured. For three of our IR-excess stars that have known radial-velocity planets, resolved imaging of the circumstellar debris disks may further offer an unprecedented view of planet-disk interactions in an extrasolar planetary system. Even non-detections of the light scattered by the circumstellar material will place strong constraints on the disk geometries, ruling out disk models with high optical depth. Unlike previous disk imaging programs, our program contains a well-defined sample of ~1 solar mass stars covering a range of ages from 3 Myr to 3 Gyr, thus allowing us to study the evolution of disks from primordial to debris for the first time. The results from our program will greatly improve our understanding of the architecture of debris disks around Sun-like stars, and will create a morphological context for the existence of our own solar system. This proposal is for a continuation of an approved Cycle 14 program {GO/10527, P.I.: D. Hines}.

WFPC2 10745


This calibration proposal is the Cycle 14 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.


Significant Spacecraft Anomalies:

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


#10372 GSAcq (2,1,1) failed due to Scan Step Limit Exceeded on FGS 2 @ 206/13:38:46z At 206/13:38:46 GSAc1 (2,1,1) failed to RGA hold due to scan step limit exceeded on FGS 2. OBADs RSS values were 3737.64 & 13.54 respectively. Possible observations affected: ACS 56. OBAD MAP scheduled @ 206/14:44:43 showed the following errors: V1 -820.84, V2 5011.53, V3 -451.42, RSS 5098.34

#10373 GSAcq (2,3,2) failed due to search radius limit exceeded on FGS 2 @ 206/17:00:47z At AOS 206/17:00:47, GSAcq (2,3,2) had failed due to search radius limit exceeded on FGS 2. OBAD #1 data unavailable due to LOS. OBAD #2 V1 43.70, V2 31.93, V3 52.14, RSS 75.15. Possible observations affected: ACS 59

#10374 GSAcq(2,1,2) failed due to search radius limit exceeded @ 207/01:14:20z.

The GSAcq(2,1,2) failed due to search radius limit exceeded on FGS 2. OBAD2 showed errors of V1=-2.03, V2=-3.48, V3=3.24, RSS=5.15. The Map at 01:16:44 showed errors of V1=1.43, V2=2.84, V3=-0.02, and RSS=3.18. Observations affected: ACS 73-79, NIC 21 and 22

#10375 GSAcq(2,1,2) failed to RGA Control @ 07:20:02z The GSAcq(2,1,2) failed to RGA Hold due to search radius limit exceeded on FGS-2. Pre-acquisition OBADs had (RSS) attitude erorr corrections values of 2943.18 and 10.66 arcseconds. Post-acquisition OBAD/MAP had 3-axis (RSS) value of 3.06 arcseconds. REacq(2,1,2) scheduled at 207/08:46:00 using same star id failed to RGA Hold. Observations affected: ACS 82,83.



#1511-1 Reset NICMOS Error Counter @ 207/02:31z

                        SCHEDULED      SUCCESSFUL
FGS GSacq                 13            09
REacq                 02            01
OBAD with Maneuver    30            30


SpaceRef staff editor.