Stellar Multiplicity With Large Spectroscopic Surveys

I will discuss our present knowledge of the statistics of stellar multiplicity: the multiplicity fraction and the distribution of periods, mass ratios, and eccentricities. These statistics have profound implications for stellar evolution, in particular for Type Ia Supernovae (SN Ia) and gravitational wave sources. I will describe how multi-epoch radial velocity measurements from large spectroscopic surveys like the Sloan Digital Sky Survey, supported by Gaia parallaxes, can open a new observational window on stellar multiplicity, and present case studies for white dwarfs and normal (non-degenerate) stars. For the white dwarfs, we can measure their merger rate, evaluate their viability as Type Ia SN progenitors, and study their properties as gravitational wave sources. For the normal stars, we can explore the interplay between stellar evolution and stellar multiplicity, measure the rate of stellar mergers, and uncover correlations between chemistry and multiplicity fraction. I will also describe how our analysis led to the discovery of the first non-interacting stellar mass black hole in the field.