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.jpg?t=eyJ3aWR0aCI6ODQ4LCJmaWxlX2V4dGVuc2lvbiI6ImpwZyIsIm9ial9pZCI6NDQ4NTkxOX0%3D--da1674c28c76b042f307f61876b4a9c06c533a0a "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=eyJ3aWR0aCI6MjQ2LCJvYmpfaWQiOjQ0ODU5MTl9--c436b13cb9df8ee9b73e91225a09cb521606af60)
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.