Nathan Harmon with Paul Harding
Improved Photometry of Metal-Poor Giants in the Kepler Field
Astroseismology is capable of measuring the properties of the interior of stars, for red giants an accurate measure of their age can then be derived. The purpose of this project is to find potentially old stars which are rare and have the least accurate ages via traditional techniques. We will determine the abundances of stars in the Kepler field, picking out metal-poor giants in the galactic halo and disk which can then be cross matched against existing Kepler observations and then submitted to the Kepler team for full analysis of the asteroseismology data to derive stellar parameters and ages. We will then in study the chemical enrichment history of the disk and halo. First we have to extend the Washington system photometric observations of the Kepler field, using the CWRU Burrell Schmidt telescope located at Kitt Peak National Observatory near Tuscon, Arizona. Once we have collected the data, we have to reduce it and measure the photometry of each star and from the Washington colors determine the metal abundances. Our photometric abundances are calibrated against well studied globular clusters. We chose metal-poor giants for their rarity and so we could have more detailed analysis done, but as now Kepler is functionally dead we have to rely on their data archives. Fortunately, they have collected a large archive and have astroseismology data for around 100,000 stars. Currently metallicity data is missing for most stars and we can only get their ages to within ~40% accuracy, but with precision abundances we can improve the accuracy to ~15%. We can also use an aggregate of our Washington photometry and the Kepler astroseismology data to look into the evolution of stars in the disk.