Obliquities and implications for binaries and exoplanets
Anders Bo Justesen, Simon Albrecht

Abstract

The formation and evolution of planetary and multiple star systems are not yet well understood. An important property of these systems is the relative orientation of the components’ rotation axes (the obliquities). To measure obliquities in a large sample of bright binary and multiple star systems we make use of SONG's effective filler observation mode and its high-resolution spectrograph. From the SONG spectra we derive projected stellar rotation speeds ($v \sin i$) and combine these with stellar rotation periods to learn about the degree of spin-spin and spin-orbit alignment. A consistent sample of precisely characterised stars is important for this work. I will present preliminary results of the investigation into the spin alignment of this sample and its relation to star and planet formation theories.