We have searched for widely separated transneptunian binaries in dithered observations using the HST Advanced Camera for Surveys High Resolution Channel. In order to automate the combining of images, we have have developed a pipeline of several scripts, utilizing the power of Python to drive the MultiDrizzle PyRAF task within STSDAS and the accessiblity of IDL to interact with the graphical display. We rely on MultiDrizzle to geometrically correct, sub-pixel shift, and drizzle multiple images of target objects. This process removes cosmic rays; with four images we find no artifacts from multiple cosmic ray hits in the drizzled images. We have examined the drizzled images for possible faint companions that would be missed in cosmic-ray impacted images. However, there are numerous image artifacts that require additional investigation to rule out possible close companions. Searching for distant, faint secondaries allows us to better understand transneptunian populations, since the fraction of binaries is a fundamental and characteristic quality. Asymmetric systems, that is, systems with a large brightness difference between primary and secondary, are common among the brightest (largest) Kuiper Belt objects (Brown et al. 2006, Brown and Suer 2007), and may be the result of collisions. Small satellites appear to be absent among the fainter (smaller) objects. A detailed search, like the one we are performing, can further constrain the roles of collisions and capture in forming binaries among the small body populations of the solar system.
AAS/Division for Planetary Sciences Meeting Abstracts #39
- Pub Date:
- October 2007