Laboratory Measurements of Electrostatic and Magnetostatic Properties of Stellar and Circumstellar Molecules

Arizona State University, Scottsdale AZ

Investigators

Abstract

Molecular spectra---the unique energy signatures of molecules---carry important information about the physical conditions of the astronomical environments in which the molecules are found. The main goal of this research project is to perform accurate laboratory measurements of key properties of molecules that are found in star spots and in the gas and dust around old stars. Accurate values of these properties will allow astronomers to extract reliable information from molecular spectra observed in these distant regions and infer the conditions present there. The project will train students and a postdoctoral researcher in advanced experimental techniques. It will also provide an advanced physical science experience to high school students and teachers at a college preparatory academy and science enrichment to local K-12 students. Using state-of-the-art spectroscopic techniques, the research team will accurately measure the electrostatic and magnetostatic properties of refractory diatomic and triatomic molecules that are known constituents of stellar atmospheres and circumstellar envelopes. The measurements will yield (1) dipole moments of AlO, AlNC, FeNC, SiCN, SiH2, SiN, SiC, HNSi, and SiCSi from optical Stark spectra; (2) magnetic g-factors of VO, CrH, FeO, TiH, and TiO from optical Zeeman measurements under magnetic fields comparable to those in star spots; and (3) electronic transition moments and spontaneous emission rates of VO, AlO, FeO, TiH, CrH, and FeH. The high quality laboratory data will allow optimum exploitation of astronomical spectra obtained with large radio and optical telescopes. Key astronomical applications include the elimination of false positives in exoplanet searches in the near-IR by accurate characterization of spectral line broadening in star spots, and the accurate determination of molecular column densities from radio observations of circumstellar envelopes. This project will train undergraduate and graduate students and a postdoctoral fellow in advanced laboratory astrophysics techniques. Additionally, the research team will conduct activities to engage students and teachers at the Arizona State University (ASU) Preparatory Academy in the physical sciences, and it will participate in ASU's "Science Is Fun" program to provide science enrichment to K-12 students, many of whom come from backgrounds underrepresented in science.