3.16 Tesis magíster

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Browsing 3.16 Tesis magíster by Author "Espinoza Rojas, Francisca"

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    The consistency of chemical clocks among coeval stars
    (2021) Espinoza Rojas, Francisca; Chanamé, Julio; Pontificia Universidad Católica de Chile. Instituto de Astrofísica
    The abundance ratios of some chemical species have been found to correlate with stellar age, leading to the possibility of using measurements of abundances in stellar atmospheres as age indicators thanks to the Galactic chemical evolution. These chemical clocks have been calibrated with solar-twins, open clusters and red giants, however, how effective they are in identifying coeval systems has not been tested for populations that sample a broader parameter space. In that sense, wide binary systems are the perfect objects to assess the applications of chemical clocks, because their components have a common origin and are separated by great distances, so they should not interact with each other, and their abundances and ages are expected to be consistent. In this thesis, I determined the abundances of a sample of 5 wide binaries and collected data for other 31 systems from the literature in order to test the applicability of chemical clocks. I found that wide binaries have more consistent abundances than random pairs. I also found that chemical clocks are even more consistent among the components of wide binaries than their [X/Fe] ratios. Not only that, but the special case of the pair HIP 34426/HIP 34407 would indicate that chemical clocks are consistent for coeval stars even when their abundances are not. Finally, given the evidence that chemical clocks trace information about stellar birthplaces and chemical evolution, I briefly studied their benefits for chemical tagging by using them to reconstruct a sample of 3 open clusters, and found that chemical clocks do not improve the identification of the cluster’s members, but could be used for decontamination. Despite this, the results are limited by the age range of the sample, and there is still much work that could be done to better evaluate this idea and find more applications for chemical clocks.