TITLE:
Influence of Supernova SN Ia Rate and the Early Star Formation Rate on the Galactic Chemical Evolution
AUTHORS:
Sandeep Sahijpal
KEYWORDS:
Galaxy Formation; Galactic Chemical Evolution; Stellar Nucleosynthesis; Star Formation; Supernovae
JOURNAL NAME:
International Journal of Astronomy and Astrophysics,
Vol.3 No.3,
September
3,
2013
ABSTRACT: Based on the recently developed numerical approach to understand
the formation and the chemical evolution of the milky-way galaxy in the solar neighborhood
we study the influence of the supernova type SN Ia rates on the galactic chemical
evolution. Supernova SN Ia plays an important role in producing the iron inventory
of the galaxy. We also study the dependence of the chemical evolution on the star
formation rate prevailing during the initial one billion years of the evolution
of the galaxy. This era marks the formation of the galactic halo and the thick disk.
A comparison of the elemental abundance distributions of the dwarf stars in the
solar neighborhood is made among the various models simulated in the present work.
In order to explain the majority of the observed elemental evolutionary trends,
specifically those related with the galactic evolution of iron and oxygen, it would
be essential to incorporate a major component of prompt SN Ia to the galactic evolution.
The prompt SN Ia would produce significant fraction of SN Ia within the initial
~100 million years from the time of star formation. The essential requirement of
prompt SN Ia would result in a significant enhancement of SN Ia rates during the
earliest epoch of the galaxy. The elemental evolutionary trends also favor an enhancement
in the star formation rate during the initial one billion years of the galaxy at
least by a factor of three compared to the trend prevailing during the latter evolutionary
time of the galaxy.