We present the results of a binary population study in the Orion Nebula Cluster (ONC) using archival Hubble Space Telescope (HST) data obtained with the Advanced Camera for Surveys (ACS) in B, V, i, and z filters (Treasury Program 10246, PI M. Robberto). Young clusters and associations may hold clues to the origin of the initial mass function as well as the properties of multiple star systems as we continue to develop a predictive theory of star formation. Low mass star-forming regions such as Taurus, reveal an excess of multiples over separation ranges sampled and perhaps unusual companion mass ratio distributions (Kraus et al. 2011; Reggiani & Meyer 2011). The Orion Nebula Cluster is a high mass star-forming region with a binary population that has been studied in the separation ranges of < 10 AU (Kounkel et al. 2016) and > 65 AU (Reipurth et al. 2007) Star clusters like the ONC could be the dominant source of the Galactic field star population and a likely birthplace for our solar system. Intermediate separation binaries might be useful as a tracer of the initial binary population since they are not likely to be destroyed through dynamical interactions (Parker & Meyer 2014). Unfortunately, the gap in our knowledge of the ONC binary population, between 10 - 65 AU, overlaps with the peak binary distribution for M and G dwarfs in the Galactic field (Raghavan et al. 2010; Janson et al. 2012). Including this new analysis, we can i) better assess whether the ONC contributes significantly to the Galactic field star population ii) compare the ONC to low mass star forming regions like Taurus, and iii) search for trends in binary properties as a function of star forming environment. We search for potential binaries by fitting a double point-spread function (PSF) model built from the empirical PSFs of Anderson & King 2006. Our sample of ONC members is representative for masses 0.1 - 1.2 M☉ (MIST 2016) assuming an age of 1 - 2Myr and confirmed with radial velocities from Da Rio et al. 2016 based on the APOGEE IN-SYNC survey. Our results will define the binary frequency and the companion mass ratio distribution of the ONC from 20 - 65 AU.
American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019