Abstract Details
| Name: Meenakshi P Affiliation: IIA, Bengaluru Conference ID: ASI2019_112 Title : Abundance of neutron-capture elements in extrinsic Carbon-Enhanced Metal-Poor stars Authors and Co-Authors : Author : Meenakshi P (1,2) , Co-authors : Aruna Goswami (1) , Vijayakumar H Doddamani (2), 1 : Indian Institute of Astrophysics, Koramangala, II block, Bangalore, Karnataka, 560034., 2 Department of Physics, Bangalore University, Jnana Bharathi Campus, Karnataka, 560056. Abstract Type : Oral Abstract Category : Stars, ISM and Galaxy Abstract : Carbon-Enhanced Metal-Poor (CEMP) stars are stars with [Fe/H] ≤ −2 and enriched in carbon ([C/Fe] > 0.7) as well as neutron-capture elements. CEMP stars are classified into different categories based on the nucleosynthetic origin of the heavy elements. CEMP stars are either subgiants or giants and hence the observed enhancement of heavy element abundances are generally attributed to an extrinsic source. Extrinsic carbon stars usually exhibit low value of carbon isotopic ratio compared to instrisic carbon stars due to the changes in the surface chemical composition caused by mass transfer and internal mixing. We have performed a detailed abundance analysis of two CEMP stars CD−28 1082 and CD−38 2151. Both the stars are found to exhibit enhancement of carbon, nitrogen and heavy elements. We have estimated carbon isotopic ratios ( 12^C/ 13^C) for the two objects with values 16 for CD−28 1082 and 11.2 for CD−38 2151. Luminosity estimates indicate that these objects are in the ascending giant branch phase where CD−38 2151 is found to be above the RGB bump. Hence the observed low value of 12^C/13^C can also be explained in the frame work of first drege-up. Thermohaline mixing and other distinct mixing episodes occuring after the RGB bump may be other possible reasons leading to low value of carbon isotopic ratios. In this talk, we will present some recent results obtained from high resolution spectroscopic analysis of CD−28 1082 and CD−38 2151. |