Abstract:
In the quest for understanding the early universe, we have come to a line of thought
of looking for Metal-poor stars since they carry the fingerprint of the very first
stars formed. The study of the elements produced or preserved in these stars
gives a fundamental insight into the chemical evolution on a much larger scale.
To understand the composition of such stars and their distribution in the galaxy,
there exists a need for High-resolution spectroscopic studies on target stars which
show neutron-capture elements enhancement. Therefore, in this work, we present
the detailed chemical abundance analysis of objects HD 179832, HD 145777 and
HE 2144-1832 using High-resolution spectra of facilities such as FEROS (Fibre-fed
Extended Range Optical Spectrograph) and HESP (High-Resolution Echelle
Spectrograph). We do a series of reductions procedures using IRAF to obtain final
spectra, followed by metallicity estimate and determining model atmosphere parameters
such as effective temperature, surface gravity and micro-turbulent velocity
of the programme stars. Then we use these to do the chemical analysis of species
such as α-elements, Fe-peak elements and neutron-capture process elements using
the latest version of spectral analysis code MOOG. We present the mass and
age of the stars determined using the up to date models of stellar evolutionary
track and isochrones.
The object HD 179832, HD 145777 and HE 2144-1832 have [Fe/H] 0.22, -
2.14 and -1.60 respectively. These are classified as Barium star, CEMP-s star and
CEMP-r/s star respectively by our analysis. We also report the analysis of more than
15 elements including α elements such as Mg, Ca, Ti; Iron-peak elements such
as Co, Ni, and Zn; light neutron-capture elements like Sr, Y and heavy neutron-capture
elements Ba, La, Nd, Sm, Eu.
At the end of the report, we attempt to classify our results with respect to the
large sample of existing literature on the concerned system. Using Kinematic
analysis and nucleosynthesis theories we present some conclusions on the galactic
distribution of these stars and origin of the elements produced by them
