NASA Hubble Space Telescope Daily Report # 4505

HUBBLE SPACE TELESCOPE DAILY REPORT # 4505

Continuing to collect World Class Science

PERIOD COVERED: UT December 11, 2007 (DOY 345)

OBSERVATIONS SCHEDULED

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz < 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a snapshot imaging survey of the sites of some of these nearby objects, to obtain late-time photometry that {through the shape of the light and color curves} will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-color and color-magnitude diagrams of stars in these SN sites, to determine the SN progenitor masses and constraints on the reddening. Recovery of the SNe in the new HST images will also allow us to actually pinpoint their progenitor stars in cases where pre- explosion images exist in the HST archive. This proposal is an extension of our successful Cycle 13 snapshot survey with ACS. It is complementary to our Cycle 15 archival proposal, which is a continuation of our long-standing program to use existing HST images to glean information about SN environments.

FGS 11228

Extrasolar Planet XO-2b

We propose observations of the newly discovered extrasolar planet XO-2b and its twin star XO-2. When combined with the transit light curve, the FGS-derived parallax will constrain the stellar mass of the host star XO-2. From the high signal-to-noise near-IR time series resulting from NICMOS grism spectroscopy, we will refine the system parameters, in particular radii of the star and planet. From the same data, we will search for evidence of water vapor in the atmosphere via transmission spectroscopy. Differential observations with NICMOS in the spectroscopic mode will be used to search for the small spectral changes that occur during planetary transits resulting from absorption of stellar light as it passes through the planetary atmosphere. Water is an important constituent, the detection of which would provide information on Oxygen, and it has a convenient strong band well- positioned for NICMOS.

FGS 11462

FGS1r, FGS2r, and FGS3 Pre-SM4 Performance

This proposal is the first of a pair of proposals that monitors the characteristics of HST’s two “continuing” Fine Guidance Sensors across the boundary of the servicing mission SM4. This proposal obtains the pre-SM4 measurements. Proposal 11463 gathers the same data but for the post-SM4 baseline. For each FGS, stars from a selected field in the standard astrometric Galactic cluster M35 are observed in Position mode. This provides a measurement of their relative positions, which in turn provides an effective means to detect and monitor any changes in the FGS optical distortions and plate scales. If out of tolerance, the need for a re- calibration of the particular FGS’s distortions will be indicated. The FGS-FGS alignments will also be monitored across the SM boundary. This will be done by using the same guide star pairs in the corrresponding proposal 11463. Finally, this proposal and 11463 include Transfer mode observations of selected M35 stars. These observations will obtain S-curves at the center and at two off-center field points in each FGS FOV. These data will provide insight as to whether or not the relative alignment of the FGS optical train with the HST OTA has changed. If changes larger than tolerance are observed, it will be necessary to activate the appropriate contingency proposal that will obtain S-curves are several locations in the FGS FOV to facilitate a re-computation of the optimal values of K-factors that are used in the acquisition and tracking of guide stars (and astrometry targets). This proposal requires a total of 4 HST orbit to support ther FGS2r and FGS3 observations. The FGS1r observations are available from the FGS Cycle 16 Astrometry calibration plan.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration – CR Persistence Part 6

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 i mages. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

WFPC2 11022

WFPC2 Cycle 15 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check.

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.

WFPC2 11226

Hubble Investigation of Comet 8P/Tuttle

Comet 8P/Tuttle is a returning nearly isotropic comet (NIC) with an outstanding apparition in cycle 16, passing within 0.25 AU of the Earth. We propose a 12-orbit Hubble investigation that will allow us to determine the size, shape, rotational period, and color (UBVRI) of 8P, thereby providing the most detailed view of a NIC nucleus since the spacecraft flyby of 1P/Halley in 1986. The return of 8P is a rare opportunity, and we expect many other observatories, including Spitzer, to be investigating this comet. Combining the Hubble results with those from other observatories should yield a comprehensive picture of this NIC that can be compared to the detailed data collected on ecliptic comets (ECs) during the past 3 decades. The differences and similarities between NICs and ECs should yield valuable insights into the origin and evolution of comets.

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               08                 08
FGS REacq               06                 06
OBAD with Maneuver      30                 30

SIGNIFICANT EVENTS: (None)