Low-resolution spectroscopy of high galactic latitude objects: a search for CH stars

Abstract

Properties of CH stars like iron deficiency and enrichment of carbon and heavy elements can provide valuable inputs to our understanding of nucleosynthesis. In particular, these parameters provide strong observational constraints for theoretical studies of nucleosynthesis of heavy elements at low- metallicity. Accurate identification and spectroscopic characterization of CH stars are therefore very essential. We have undertaken a programme with a prime ob jective to search for these ob jects in a mixed sample of carbon stars taken from Hamburg/ESO survey. The spectra of the ob jects were obtained using OMR at VBO, Kavalur and HFOSC at HCT, IAO, Hanle, during 2005 and 2006. Here, we report a detection of twenty-one CH stars from a sample of sixty ob jects based on low-resolution spectral analysis. Estimated effective temperatures, 12 C/13 C isotopic ratios, and their location in the two colour J-H vs H-K plot support their identification with the class of CH stars. Detection of these potential CH star candidates and their spectral description is the main theme of this paper.