#  ITC Colloquium - David Weinberg (OSU) 

 



####  calendar\_today Date and Time 

 **September 20, 2018** 

 11:00AM - 12:00PM EDT 

####  pin\_drop Location 

 **Pratt**  



 

 



 

 "Decoding Chemical Evolution and Nucleosynthesis"

 I will discuss insights from analytic and numerical models of  
galactic chemical evolution and observations of Milky Way  
elemental abundances from the SDSS APOGEE survey. Under  
generic model assumptions, abundances and abundance ratios  
approach an equilibrium in which element production from  
nucleosynthesis is balanced by element depletion from star  
formation and outflows. Reproducing solar abundances requires  
outflows with mass-loading factors of 1-3, but one can evade  
this conclusion by assuming low stellar yields or metal-enhanced  
winds; the high observed deuterium abundance of the local ISM  
argues against these alternatives and in favor of outflows.  
Starbursts or other sudden transitions can produce temporary  
boosts in alpha-to-iron ratios, and other surprising behavior  
such as backward evolution of a stellar population from high  
metallicity to low metallicity. APOGEE observations show   
that the distributions of stars in (alpha,iron,age)-space change  
steadily across the Milky Way disk. Given these distributions,  
the behavior of other APOGEE abundance ratios can be explained   
by changes in the ratio of core collapse to Type Ia supernova  
enrichment. The separability of "multi-element cartography"  
offers a route to empirically constraining supernova yields  
in a way that is insensitive to uncertainties in other aspects  
of chemical evolution.



 

 



 

 See also:- [ 2018 - 19 ](/academic-year/2018-19)
- [ Colloquium ](/event-type/colloquium)
 
 

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