AAVSO: American Association of Variable Star Observers

How to Use Astronomical Spectroscopy to Turn the Famous Yellow Sodium Doublet D Bands into a Stellar Speedometer and Thermometer (Abstract)

Volume 45 number 2 (2017)

Joshua Christian, Matthew King, John W. Kenney III
Chemical Physics Laboratory, Concordia University, 1530 Concordia West, Irvine, CA 92612

Abstract

(Abstract only) The twin, closely spaced D bands of sodium, which appear in the spectra of many stars, turn out to be easy to identify and, owing to their intensity, easy to use as “speedometer bands” via spectral Doppler shifts for the analysis of differential radial velocities in binary star systems and other systems for which astronomical velocity measurements are needed. Moreover, temperature data can be extracted from an analysis of the widths of the sodium band profiles. In order to demonstrate the effectiveness of these techniques and calculations, terrestrial sources of sodium and a simulated Doppler shift were used. A visible and quantifiable difference in band profile widths was seen corresponding to temperature, encouraging further studies.