Spectroscopic Surveys
![Observed mono-abundance stellar populations (MAPs) in the Milky Way disk. The plot shows the correlation between the radial scale length and the vertical scale height of MAPs, color-coded by [α/Fe]. The size of the points corresponds to the total stellar surface-mass density—corrected for mass and sample selection effects—in each population. MAPs appear to have a simple spatial structure, approximated by a single exponential in the radial and vertical directions.](/4485919/original-1518438323.webp?t=eyJ3aWR0aCI6MTY5NiwiZmlsZV9leHRlbnNpb24iOiJ3ZWJwIiwib2JqX2lkIjo0NDg1OTE5fQ%3D%3D--27810fb8224addad196de85dc379617ab1258f59 "Observed mono-abundance stellar populations (MAPs) in the Milky Way disk. The plot shows the correlation between the radial scale length and the vertical scale height of MAPs, color-coded by [α/Fe]. The size of the points corresponds to the total stellar surface-mass density—corrected for mass and sample selection effects—in each population. MAPs appear to have a simple spatial structure, approximated by a single exponential in the radial and vertical directions.")
![Observed mono-abundance stellar populations (MAPs) in the Milky Way disk. The plot shows the correlation between the radial scale length and the vertical scale height of MAPs, color-coded by [α/Fe]. The size of the points corresponds to the total stellar surface-mass density—corrected for mass and sample selection effects—in each population. MAPs appear to have a simple spatial structure, approximated by a single exponential in the radial and vertical directions.](/4485919/original-1518438323.jpg?t=eyJ3aWR0aCI6MTM3OCwib2JqX2lkIjo0NDg1OTE5fQ%3D%3D--4786c3c554cd6e2ba0c2a76e1807a7be9b322d4e)
Observed mono-abundance stellar populations (MAPs) in the Milky Way disk. The plot shows the correlation between the radial scale length and the vertical scale height of MAPs, color-coded by [α/Fe]. The size of the points corresponds to the total stellar surface-mass density—corrected for mass and sample selection effects—in each population. MAPs appear to have a simple spatial structure, approximated by a single exponential in the radial and vertical directions.
MPIA/Bovy et al 2012
Spectroscopic surveys, such as SDSS-IV, provide stellar parameters, ages, and abundances.