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=ZXlKM2FXUjBhQ0k2TVRZNU5pd2labWxzWlY5bGVIUmxibk5wYjI0aU9pSjNaV0p3SWl3aWIySnFYMmxrSWpvME5EZzFPVEU1ZlE9PS0tMjc4MTBmYjgyMjRhZGRhZDE5NmRlODVkYzM3OTYxN2FiMTI1OGY1OQ "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=ZXlKM2FXUjBhQ0k2TVRNM09Dd2liMkpxWDJsa0lqbzBORGcxT1RFNWZRPT0tLTQ3ODZjM2M1NTRjZDZlMmJhMGMyYTc2ZTE4MDdhN2JlOWIzMjJkNGU)
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.