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Full-Text Articles in Physical Sciences and Mathematics
Rr Lyrae Calibration Using Sdss, Single-Epoch Spectroscopy, Stacy Long
Rr Lyrae Calibration Using Sdss, Single-Epoch Spectroscopy, Stacy Long
Theses and Dissertations--Physics and Astronomy
I use single-epoch, SDSS spectroscopy of RR Lyraes identified in the Catalina survey to separate the spectra into same-temperature groups. Then I draw temperature-phase diagrams of the groups. I find shocked stars, improperly phased stars, low amplitude stars, and a few that are more likely eclipsing binaries. The RR Lyraes are then given precise metallicities by measurements of the CaII K and H-β, H-γ, and H-δ lines. This leads to better distance measurements, which allow me to confirm a distinction between the inner and outer galactic halo.
A New Set Of Spectroscopic Metallicity Calibrations For Rr Lyrae Variable Stars, Eckhart Spalding
A New Set Of Spectroscopic Metallicity Calibrations For Rr Lyrae Variable Stars, Eckhart Spalding
Theses and Dissertations--Physics and Astronomy
RR Lyrae stars are old, iron-poor, Helium-burning variable stars. RR Lyraes are extremely useful for tracing phase-space structures and metallicities within the galaxy because they are easy to identify, have consistent luminosities, and are found in large numbers in the galactic disk, bulge, and halo. Here we present a new set of spectroscopic metallicity calibrations that use the equivalent widths of the Ca II K, Hγ, and Hδ lines to calculate metallicity values. Applied to spectroscopic survey data, these calibrations will help shed light on the evolution of the Milky Way and other galaxies.