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SUMMARY:Sabyasachi Goswami (SISSA\, Trieste\, Italy)
DTSTART:20210325T143000Z
DTEND:20210325T153000Z
DTSTAMP:20260423T035936Z
UID:CENTRA/37
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/CENTRA/37/">
 On the effects of Initial Mass function on the galactic chemical enrichmen
 t</a>\nby Sabyasachi Goswami (SISSA\, Trieste\, Italy) as part of CENTRA S
 eminar\n\n\nAbstract\nContext: There is mounting evidence that the stellar
  initial mass function (IMF) could extend much beyond the canonical Mi ~10
 0\, Msun limit\, but the impact of such hypothesis on the chemical enrichm
 ent of galaxies still remains to be clarified.\n\nAim: We aim to address t
 his question by analysing the observed abundances of thin- and thick-disc 
 stars in the Milky Way with chemical evolution models that account for the
  contribution of very massive stars dying as pair-instability supernovae.\
 n\nMethod: We built new sets of chemical yields from massive and very mass
 ive stars up to  Mi ~ 350 Msun\, by combining the wind ejecta extracted fr
 om our hydrostatic stellar evolution models with explosion ejecta from the
  literature. Using a simple chemical evolution code we analyse the effects
  of adopting different yield tables by comparing predictions against obser
 vations of stars in the solar vicinity.\n\nResults: After several tests\, 
 we focus on the [O/Fe] ratio which best separates the chemical patterns of
  the two Milky Way components. We find that with a standard IMF\, truncate
 d at Mi ~ 100 Msun\, we can reproduce various observational constraints fo
 r thin-disc stars\,  but the same IMF  fails to account for the [O/Fe] rat
 ios of thick-disc stars. The best results are obtained by extending the IM
 F up to  Mi = 350 Msun and including the chemical ejecta of very massive s
 tars\, in the form of winds and pair-instability supernova explosions.\n\n
 Conclusions: Our study indicates that PISN played a significant role in sh
 aping the chemical evolution of the Milky Way thick disc. By including the
 ir chemical yields it is easier to reproduce not only the level of the alp
 ha-enhancement but also the observed slope of thick-disc stars in the [O/F
 e] vs [Fe/H] diagram. The bottom line is that the contribution of very mas
 sive stars to the chemical enrichment of galaxies is potentially quite imp
 ortant and should not be neglected in chemical evolution models.\n
LOCATION:https://researchseminars.org/talk/CENTRA/37/
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