HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4719

PERIOD COVERED: 5am October 17 - 5am October 20, 2008 (DOY 291/0900z-294/0900z)

OBSERVATIONS SCHEDULED

FGS 11901

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)

                        SCHEDULED      SUCCESSFUL

FGS GSacq                17                  17                                        

FGS REacq                15                  15                    

OBAD with Maneuver  40                  40                      

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS: None