Sep 17, 2012

Saurav Dhital, Vanderbilt University

"SLoWPoKES: A Cool Stars Resource for Constraining Binary Formation Theory and Testing Fundamental Properties"

I will talk about the the SLoWPoKES catalogs of ultra-wide (>1000 AU), low-mass binary pairs. The initial catalog comprised of 1342 common proper motion binaries, while SLoWPoKES-II consists of >100,000 pairs albeit without proper motion matching. We used a Galactic model, based on on empirical stellar number density and space velocity distributions, to select bona fide pairs with probability of chance alignment <5%, making SLoWPoKES an efficient sample for followup observations.  The diversity--in mass, metallicity, age, and evolutionary states--of SLoWPoKES pairs makes it a valuable resource of coeval laboratories to examine and constrain the physical properties of low-mass stars. SLoWPoKES pairs show signatures of two (or more) formation modes in the distribution of the physical separation and higher-order multiplicity: neither dynamical dissipation of primordial triples/quadruples nor dynamical capture of ejected stars can explain he observed populations by itself. We use followup spectroscopic observations to recalibrate the metallicity-sensitive ζTiO/CaH index by assuming that both members of the binary system have the same composition. Our new formulation is a significantly better tracer of absolute metallicity, particularly for the early-type M dwarfs. The catalogs are publicly available on a custom data visualization portal.