A recent Lindblad resonance in the solar neighbourhood

Abstract

Stars in the solar neighbourhood do not have a smooth distribution of velocities. Instead, the distribution of velocity components in the Galactic plane manifests a great deal of kinematic substructure. Here I present an analysis in action-angle variables of the Geneva-Copenhagen survey of 14 000 nearby F & G dwarfs with distances and full space motions. I show that stars in the so-called 'Hyades stream' have both angle and action variables characteristic of their having been scattered at an inner Lindblad resonance of a rotating disturbance potential. This discovery seems to favour spiral patterns as recurrent, short-lived instabilities. © 2010 The Author. Journal compilation © 2010 RAS.