HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4755

PERIOD COVERED: 5am December 11 - 5am December 12, 2008 (DOY

                           346/1000z-347/1000z)

OBSERVATIONS SCHEDULED

ACS/SBC 11110

Searching for Lyman Apha Emission from FUSE Lyman Continuum Candidates

We have recently been granted time on FUSE to characterize the escape

fraction of hydrogen Lyman continuum (Lyc) photons from a

morphologically diverse set of star forming galaxies. The FUSE program

is designed to provide ~ 5 sigma detections of Lyc photons emitted from

star forming galaxies with escape fractions ~5%. With this proposal we

seek hydrogen Lyman alpha (Lya) observations of a representative subset

of the FUSE program targets to constrain the observational relationship

between Lyc, Lya, and hydrogen Balmer line emission in these systems.

Such observations explore the detailed balance between the simple

optically thin (Case A) and optically thick (Case B) limits in

recombination theory. The ultimate goal of this program is to quantify

the relationship between escaping Lya and Lyc emission and the first

structures that form in the early universe.

FGS 11942

Increasing the Accuracy of HST Astrometry with FGS1R

We propose to observe six exoplanetary system host stars and two

planetary nebulae central stars with FGS1r. All objects have been

previously observed under proposals GO-09233, -09969, -10989, and

-11210. These observations will significantly extend the time baseline,

permitting improvements in the determination of proper motion. This

systematic motion must be removed to get at the perturbation of

interest, either due to exoplanetary companions or the orbital motion of

the Earth (parallax). In most cases the perturbation orbits will also

improve. We improve either companion mass or PN parallax. For one

target, GJ 876, theoretical dynamical modelers have proposed an

inclination closer to 50 degrees, while FGS3 measurements indicated an

inclination closer to 84 degrees. These new data, once combined with our

older FGS3 data, will permit an independent remeasurement of the

inclination of the outermost companion, and a re-evaluation of widely

used dynamical algorithms.

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.

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               07                  07                              

FGS REacq               00                  00                 

OBAD with Maneuver 14                  14               

SIGNIFICANT EVENTS:

FLASH Report:

The "final" expected NCS CPL Reservoir temperature setpoint adjustment

was commanded to +22 degC at 345/23:03:03 UTC.

Some initial signs of the onset of a flood condition were noted at

345/17:41:00 UTC following the setpoint increase to +20 degC, but the

loop stabilized nicely and has been able to sustain the additional

2-degree increase since that time. Since the initial Reservoir setpoint

change at 345/14:22:01 UTC, the Circulator Housing temperature

(MNCIHSGT) has increased 0.75 K from 279.66 K to 280.41 K.