• MEENAKSHI PURANDARDAS

      Articles written in Journal of Astrophysics and Astronomy

    • Abundances of neutron-capture elements in CH and carbon-enhanced metal-poor (CEMP) stars

      MEENAKSHI PURANDARDAS ARUNA GOSWAMI

      More Details Abstract Fulltext PDF

      All the elements heavier than Fe are produced either by the slow (-s) or rapid (-r) neutroncapture process. The neutron density prevailing in the stellar sites is one of the major factors that determines the type of neutron-capture processes. We present the results based on the estimates of corrected value of absolute carbon abundance, [C/N] ratio, carbon isotopic ratio and [hs/ls] ratio obtained from the highresolution spectral analysis of six stars that include both CH stars and CEMP stars. All the stars show enhancement of neutron-capture elements. Location of these objects in the A(C) vs. [Fe/H] diagram shows that they are Group I objects, with external origin of carbon and neutron-capture elements. Low values of carbon isotopic ratios estimated for these objects may also be attributed to some external sources. As the carbon isotopic ratio is a good indicator of mixing, we have used the estimates of ${}^{12}$C/${}^{13}$C ratios to examine the occurrence of mixing in the stars. While the object HD 30443 might have experienced an extra mixing process that usually occurs after red giant branch (RGB) bump for stars with log(L/L$_{\odot}$)>2.0, the remainingobjects do not show any evidence of having undergone any such mixing process. The higher values of [C/N] ratios obtained for these objects also indicate that none of these objects have experienced any strong internal mixing processes. Based on the estimated abundances of carbon and the neutron-capture elements, and the abundance ratios, we have classified the objects into different groups. While the objects HE 0110-0406, HD 30443 and CD-38 2151 are found to be CEMP-s stars, HE 0308-1612 and HD 176021 show characteristicproperties of CH stars with moderate enhancement of carbon. The object CD-28 1082 with enhancement of both r- and s-process elements is found to belong to the CEMP-r/s group.

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.