Highlight: The formation of a thick disk through the heating of a thin disk [...] (vol. 525)

Vol. 525In section 1. Letters30 November 2010

The formation of a thick disk through the heating of a thin disk: Agreement with orbital eccentricities of stars in the solar neighborhood

by P. Di Matteo, M. D. Lehnert, Y. Qu, and W. van Driel, A&A 525, L3 alt

The formation of a thick stellar disk in spiral galaxies like the Milky Way could come from at least 4 mechanisms: heating of the thin disk through gravitational instabilities, radial migration, minor mergers, or accretion of satellites. It has recently been proposed to use the orbital eccentricity of stars in the thick disk as a way of constraining these mechanisms. The authors ran numerical simulations to show that the observed distribution of orbital eccentricities of stars in the galactic thick disk qualitatively agrees with a scenario where the thick disk has been formed by heating the thin disk through the impact of minor mergers.