Title

Abundance Patterns in the Spiral Galaxy Messier 33

Author Info

Melissa A. Siemer, STEM Teacher and Researcher ProgramFollow
Ravi Sankrit, SOFIA Science Center

Recommended Citation

January 1, 2013.

Abstract

Messier 33 (M33) is a spiral disk galaxy, similar to our galaxy, approximately 3 million light-years from Earth. Because of its proximity to Earth and face-on viewing angle, it is easy to see individual objects. Consequently, M33 is in an ideal position for obtaining data on elemental abundances. By studying M33, we learn how galaxies like our own form and change over time.

We use published optical spectroscopic data, obtained and assembled from online sources, to map the abundances of various elements (Helium, Nitrogen, Oxygen, Neon, Argon, Sulfur) in the planetary nebula and HII region populations of M33. We classify the locations within the galaxy of each object in three ways: according to spiral arms, the location of star-forming regions, and in azimuthal sectors assuming the nucleus of the galaxy is the center. We examine the distribution of elements according to these locational overlays to find any visual patterns among position and abundance, then perform a statistical hypothesis test for difference in abundances for positions. We take elemental abundances and graph them against each other for each object in each location, finding the correlation coefficient and the least squares regression line for each pair.

Disciplines

External Galaxies | Stars, Interstellar Medium and the Galaxy

Mentor

Ravi Sankrit

Lab site

NASA Ames Research Center (ARC)

Funding Acknowledgement

This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).