• Skip to content
  • Skip to footer

Iowa Space Grant Consortium

  • Home
  • About
    • ISGC Team
  • Funding Calendar
  • Students
    • Undergrads
    • Graduate Students
    • Student Reports
      • Undergraduate Students
      • Graduate Students
      • Symposium 2020 Reports
    • Alumni Stories
  • Internships
    • NASA Internships
    • Internship Opportunities
    • Internship Reports
  • Faculty
  • Education & Outreach
    • Precollege (K-12 Educators)
    • ASTRO CAMP
    • 2023 & 2024 Solar Eclipse
    • Space Week Challenge
  • Forms Repository
    • Faculty Forms & Reports
    • Student Forms & Reports
  • Announcements
  • Links
    • Links
    • Iowa NASA EPSCoR
    • NASA Resources
    • NASA Solar System Ambassadors
  • ISGC Student Research Symposium

Keith Doore

December 20, 2016

Student: Keith Doore, Undergraduate Student in Earth Science, University of Northern Iowa
Research Mentor: Siobahn Morgan

Using Fourier Coefficients to Examine the Metallicity of the Milky Way and Other Galaxies

The research project I am pursuing is examining RR Lyrae stars in the region of the Galactic bulge from OGLE (Optical Gravitational Lensing Experiment) IV data acquiredKeith Doore Action Photo in 2014. Using the I band light curves of these variables, I have derived the Fourier coefficients, Rij and ϕij, from a Fourier transform. Rij and ϕij relate to the amplitude and phase terms respectively, of the light variation over a pulsation period. In order to use these terms, I have had to take into account the use of I magnitudes since most other studies use B or V magnitude values. I am doing this by revising a current I to V band Fourier coefficient relation from Morgan et al., 1998. To revise this relation, I have gathered other RR Lyrae data from various globular clusters within the galaxy that contain both I and V band data. With this data, I have had to determine “well-behaved” stars, which can be used to determine a relation between the I and V band Fourier coefficients. Then, these new Fourier coefficients along with the pulsation period of the stars will be used to derive the metallicity of the OGLE IV RR Lyrae. The metallicity of these stars will then be compared to similar stars in this location from other metallicity studies. If successful, this I to V band formula will replace existing formulas and be applied to other datasets in the OGLE database, including the larger RR Lyrae catalogs for the Large and Small Magellanic Clouds.

Footer

Follow us on social media:

NASA Logo Space Grant Logo

Copyright © 2023 · Iowa Space Grant Consortium · All Rights Reserved
The Iowa Space Grant Consortium is primarily funded through a NASA Cooperative Grant.

Links · Log in

  • Drake University
  • Iowa State University
  • University of Iowa
  • University of Northern Iowa
  • Des Moines Area Community College
  • Loras College
  • Morningside University