Oscar Agertz
Associate Professor / Senior university lecturer / Wallenberg Academy Fellow
Constraining churning and blurring in the Milky Way using large spectroscopic surveys - An exploratory study
Author
Summary, in English
We have investigated the possibilities to quantify how much stars move in theMilkyWay disc due to diffuse processes (blurring) and due to influences from spiral arms and the bar (churning). We assume that the formation radius of a star can be inferred if we know its elemental abundances and age and the metallicity profile of the interstellar medium at the time of the star's formation. We use data for red giant branch stars from APOGEE DR14, parallaxes from Gaia, and stellar ages based on the C and N abundances. In our sample, we find that half of the stars have experienced some sort of radial migration, 10 per cent likely have suffered only from churning, and a modest 5-7 per cent have never experienced either churning or blurring making them ideal tracers of the original properties of the cool stellar disc. To arrive at these numbers, we imposed the requirement that the stars that are considered to be churned have highly circular orbits. If instead we require that the star has moved away from its formation position and at the same time that its Galactocentric radius at formation did not fall between the apo- and pericentre of its orbit today, we find that about half of the stars have undergone a radial migration. We have thus shown that it is possible to put up a framework to quantify churning and blurring. Future work includes investigations of how selection effects influence the results.
Department/s
- Lund Observatory - Has been reorganised
- eSSENCE: The e-Science Collaboration
Publishing year
2020
Language
English
Pages
1419-1433
Publication/Series
Monthly Notices of the Royal Astronomical Society
Volume
493
Issue
1
Document type
Journal article
Publisher
Oxford University Press
Topic
- Astronomy, Astrophysics and Cosmology
Keywords
- Galaxy: evolution
- ISM: abundances
- Stars: kinematics and dynamics
Status
Published
ISBN/ISSN/Other
- ISSN: 0035-8711