Spatial variations in the Milky Way disc metallicity-age relation

Feuillet, Diane K.Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany (författare)

Stellar ages are a crucial component to studying the evolution of the Milky Way. Using Gaia DR2 distance estimates, it is now possible to estimate stellar ages for a larger volume of evolved stars through isochrone matching. This work presents [M/H]-age and [alpha/M]-age relations derived for different spatial locations in the Milky Way disc. These relations are derived by hierarchically modelling the star formation history of stars within a given chemical abundance bin. For the first time, we directly observe that significant variation is apparent in the [M/H]-age relation as a function of both Galactocentric radius and distance from the disc midplane. The [M/H]-age relations support claims that radial migration has a significant effect in the plane of the disc. Using the [M/H] bin with the youngest mean age at each radial zone in the plane of the disc, the present-day metallicity gradient is measured to be -0.059 +/- 0.010 dex kpc(-1), in agreement with Cepheids and young field stars. We find a vertically flared distribution of young stars in the outer disc, confirming predictions of models and previous observations. The mean age of the [M/H]-[alpha/M] distribution of the solar neighbourhood suggests that the high-[M/H] stars are not an evolutionary extension of the low-alpha sequence. Our observational results are important constraints to Galactic simulations and models of chemical evolution.

Frankel, NeigeMax Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany (författare)
Lind, KarinUppsala universitet,Observationell astrofysik,Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany(Swepub:uu)karli488 (författare)
Frinchaboy, Peter M.Texas Christian Univ, Dept Phys & Astron, Ft Worth, TX 76129 USA (författare)
Garcia-Hernandez, D. A.IAC, E-38205 Tenerife, Spain;ULL, Dept Astrofis, E-38205 Tenerife, Spain (författare)
Lane, Richard R.Pontificia Univ Catolica Chile, Inst Astrofis, Av Vicuna Mackenna 4860, Santiago 7820436, Chile;Millennium Inst Astrophys, Av Vicuna Mackenna 4860, Santiago 7820436, Chile (författare)
Nitschelm, ChristianUniv Antofagasta, Ctr Astron CITEVA, Ave Angamos 601, Antofagasta 1270300, Chile (författare)
Roman-Lopes, AlexandreUniv La Serena, Fac Ciencias, Dept Fis, Cisterns 1200, La Serena, Chile (författare)
Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, GermanyObservationell astrofysik (creator_code:org_t)

Ingår i:Monthly notices of the Royal Astronomical Society: Oxford University Press (OUP)489:2, s. 1742-17520035-87111365-2966

Av författaren/redakt...: Feuillet, Diane ...; Frankel, Neige; Lind, Karin; Frinchaboy, Pete ...; Garcia-Hernandez ...; Lane, Richard R.; visa fler...; Nitschelm, Chris ...; Roman-Lopes, Ale ...; visa färre...

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