2003/10/31 by Richard S. De Simone, Xiaoan Wu, Scott Tremaine · 3 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.07675.x
published as Mon.Not.Roy.Astron.Soc. 350 (2004) 627 · Accepted by MNRAS for publication; 20 pages, 11 figures, mn2e.cls
arxiv created 2004/01/29 · openalex publication_date 2004/04/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We explore the heating of the velocity distribution in the solar neighbourhood by stochastic spiral waves. Our investigation is based on direct numerical integration of initially circular test-particle orbits in the sheared sheet. We confirm the conclusion of other investigators that heating by spiral structure can explain the principal features of the age–velocity dispersion relation and other parameters of the velocity distribution in the solar neighbourhood. In addition, we find that heating by strong transient spirals can naturally explain the presence of small-scale structure in the velocity distribution (‘moving groups’). Heating by spiral structure also explains why the stars in a single velocity-space moving group have a wide range of ages, a result that is difficult to understand in the traditional model in which these structures result from inhomogeneous star formation. Thus we suggest that old moving groups arise from irregularities in the Galactic potential rather than from irregularities in the star formation rate.