JINAbase—A Database for Chemical Abundances of Metal-poor Stars

Abstract

Reconstructing the chemical evolution of the Milky Way is crucial for understanding the formation of stars, planets, and galaxies throughout cosmic time. Different studies associated with element production in the early universe and how elements are incorporated into gas and stars are necessary to piece together how the elements evolved. These include establishing chemical abundance trends, as set by metal-poor stars, comparing nucleosynthesis yield predictions with stellar abundance data, and theoretical modeling of chemical evolution. To aid these studies, we have collected chemical abundance measurements and other information, such as stellar parameters, coordinates, magnitudes, and radial velocities, for extremely metal-poor stars from the literature. The database, JINAbase, contains 1659 unique stars, 60% of which have [Fe/H] ≤ −2.5. This information is stored in an SQL database, together with a user-friendly queryable web application (http://jinabase.pythonanywhere.com). Objects with unique chemical element signatures (e.g., r-process stars, s-process and CEMP stars) are labeled or can be classified as such. We find that the various neutron-capture element signatures occur in up to 19% of metalpoor stars with [Fe/H] ≤ −2.0, and 32% when also considering carbon enhancement. The web application enables fast selection of customized comparison samples from the literature for the aforementioned studies and many more. Using multiple entries for three of the most well-studied metal-poor stars, we evaluate systematic uncertainties of chemical abundance measurements between the different studies. We provide a brief guide to the selection of chemical elements for model comparisons for non-spectroscopists who wish to learn about metal-poor stars and the details of chemical abundance measurements. Key words: astronomical databases: miscellaneous – catalogs – nuclear reactions, nucleosynthesis, abundances – stars: abundances – stars: Population II