Multiplicity in Star Formation: Close Binaries in Chamaeleon I and Taurus-Auriga

A large fraction of stars are members of binary systems. Yet, the formation and early evolution of binary and multiple stars is not well understood theoretically and poorly constrained observationally. We present findings from a comprehensive spectroscopic survey for close binaries among nearly 200 members of the Chamaeleon I and Taurus‐Auriga star‐forming regions. We find that higher mass stars in our sample have a higher spectroscopic binary frequency than their lower mass counterparts, similar to what is seen in the field and for resolved (wide) binaries in young associations. More intriguingly, our observations also reveal a significantly larger fraction of tight binaries in Tau‐Aur compared to Cha I, both for F‐K stars and for M dwarfs, implying possible regional variations in the formation of multiple stars.