NASA Hubble Space Telescope Daily Report #4721

HUBBLE SPACE TELESCOPE DAILY REPORT #4721

Continuing to collect World Class Science

PERIOD COVERED: 5am October 21 – 5am October 22, 2008 (DOY 295/0900z-296/0900z)

OBSERVATIONS SCHEDULED

FGS 11212 & 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)

COMPLETED OPS NOTES: (None)

                        SCHEDULED      SUCCESSFUL
FGS GSacq               10              10
FGS REacq               00              00
OBAD with Maneuver      20              20

SIGNIFICANT EVENTS: (None)