Dynamic Spectra of Small-Mass Meteors

Abstract. We present dynamic (22 frames per second) observations of optical spectra of small-mass (2–200 mg) meteors observed with an EMCCD imager equipped with a diffraction grating. This observational campaign occurred at Arecibo, Puerto Rico during May 2012, resulting in eight hours of clear data over four nights. We detected 22 meteors with this setup and their spectra showed varying compositions, including evidence of Na, Mg, Fe, and Ca. Spectral lines persisting over multiple frames (up to 23 frames) with sufficient signal, showed evidence for differential ablation. Brighter, more massive meteors had stronger and varied spectral signals, which showed that the temporal and spectral resolution of the faintest meteors approached the noise level of the camera system. Optical and spectral detections of these small-mass meteors provide a greater understanding of the composition of the milligram-sized population of meteors.