Poster Open Access

Measuring CO Isotopic Abundance Ratios in Solar Twin Stars

David Coria; Ian Crossfield; Joshua Lothringer

This research project seeks to: (1) test the feasibility of determining stellar ages from isotopic measurements; and (2) identify how unexplored stellar abundances correlate with galactic chemical evolution, formation, interior, age, metallicity, activity, and planetary properties for a wide range of host stars. Past isotopic searches have been hindered by limited sensitivity & resolution, strong telluric absorption, and the opacity due to millions of other molecular absorption lines that dominate the observed spectrum of cool stars. Now, however, isotopic abundance analysis is not only possible via high resolution spectroscopy but is also the next logical step for many cool stars. I am measuring the first multi-isotopic abundances in a sample of FGKM stars to identify possible discrepancies in planetary chemical evolution and accretion models. These isotopic abundance measurements may provide a new means of determining stellar ages and help identify the “missing link” between current Galactic Chemical Evolution models and inconsistent observations. Since most of spectral lines useful in isotopic analysis have low statistical significance and are barely discerned by eye when considered individually, I use a custom list of the strongest lines and create a single line profile for each isotopologue. We create a single, high- S/N line profile by taking the weighted mean, after continuum-normalizing, of each line to create a stacked absorption line. I then create corresponding line profiles for synthetic stellar models corresponding to various enrichments of the targeted isotopologue and compare them to the observed spectra in order to determine final abundances. I will repeat this process for a sample of solar twins, stars in FGK(+M) binaries, stars in known moving groups, and (eventually) any exoplanet host stars that exhibit isotopic signatures.  This will supply provide host star parameters for the currently lacking database as well as the necessary foundations for corollary exoplanet characterization studies and ultimately contribute to the exploration of galactic, stellar, and planetary origins and evolution.

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