HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4712

PERIOD COVERED: 5am October 7 - 5am October 8, 2008 (DOY 281/0900z-282/0900z)

OBSERVATIONS SCHEDULED

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is

seriously incomplete for systems in the period range from years to

millennia because the radial velocity variations are too small and the

angular separations too close for easy detection. Here we propose to

discover binaries in this observational gap through a Faint Guidance

Sensor SNAP survey of relatively bright targets listed in the Galactic O

Star Catalog. Our primary goal is to determine the binary frequency

among those in the cluster/association, field, and runaway groups. The

results will help us assess the role of binaries in massive star

formation and in the processes that lead to the ejection of massive

stars from their natal clusters. The program will also lead to the

identification of new, close binaries that will be targets of long term

spectroscopic and high angular resolution observations to determine

their masses and distances. The results will also be important for the

interpretation of the spectra of suspected and newly identified binary

and multiple systems.

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                12                  12                                                

FGS REacq                00                  00                     

OBAD with Maneuver 24                   24                        

SIGNIFICANT EVENTS: (None)