Solving some r-process issues in chemical evolution Ralph Schönrich (Oxford) Paul McMillan, Laurent Eyer, Walter Dehnen James Binney, Michael Aumer, Luca Casagrande Martin Asplund, David Weinberg Hokotezaka et al. (2018) Chemical evolution gas inflow/onflow IGM stars Chemical evolution gas Fe-rich inflow/onflow SNIa SNII+Ib,c IGM a-rich progenitors stars Chemical evolution gas Fe-rich inflow/onflow SNIa SNII+Ib,c IGM a-rich r-process progenitors outflow NM stars Hokotezaka et al. (2018) Some simple thoughts Assume constant loss fraction from yields What about the thick disc ridge? Neutron star mergers → r process later Doing a simple model Doing a simple model Chemical evolution gas Fe-rich inflow/onflow SNIa SNII+Ib,c IGM a-rich r-process progenitors outflow NM stars Trying to escape the usual links Hot air does not only make you fly, it can delay your evolution Short-lived isotopes in the early solar system Wasserburg et al. (2006) Chemical evolution gas condensation warm cool evaporation Fe-rich inflow/onflow direct enrichment SNIa SNII+Ib,c IGM a-rich r-process progenitors outflow NM stars Introducing the hot gas phase Introducing the hot gas phase Some simple thoughts Assume constant loss fraction from yields What about the thick disc ridge? Neutron star mergers → r process later Some simple thoughts Assume constant loss fraction from yields What about the thick disc ridge? Neutron star mergers → r process later Using the different factor Using the different factor Summary The hot vs. cold ISM is central for the evolution of „early“ elements Neutron star mergers (at reasonable DTDs) cannot be the dominant source of r process in Classical chemical evolution models Neutron star mergers feasible when involving hot/cold ISM „Abundance gradients“ can be inverted by inside-out formation (next pages) What's going on with gradients? Schoenrich & McMillan (2017) Inverting gradients normalisation SFR churning blurring ISM metallicity Inverting gradients Stellar metallicity ISM metallicity SFR Radial mixing Inverting gradients specific SFH Total SF Put all painful steps as trivial exercise into the problem set Inverting gradients Everyone has solved this already Gradient profiles Lee et al. (2012) Stellar kinematics profile S & M 2017 The significance of kinematic trends Stellar densities in the [Fe/H]-[O/Fe] plane stellar radial migration forms naturally the two ridges no gap in star formation or merger needed „thick disc“ log(density) „upper“ part of ISM trajectories ISM trajectories 10 7.5 5 2.5 kpc „thin disc“ not the consequence of a local ISM trajectory near „endpoints“ of ISM trajectories density contours 0.5 dex Schoenrich & Binney (2009b) NM to hot phase Different SNIa DTD.