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Infrasound Detections of Large Bolides

Presentation #510.01 in the session Asteroids: Planetary Defense (Oral Presentation)

Published onOct 23, 2023
Infrasound Detections of Large Bolides

Meteoroids and asteroids are of immense scientific value. A meteoroid’s passage through dense regions of the Earth’s atmosphere results in a visual phenomenon (or a meteor) through the variety of processes, including heating, sputtering, and ablation. Very bright meteors, also referred to as fireballs and bolides, are generally produced by objects greater than about 10 cm in diameter. However, larger objects (10s of meters in size) have destructive potential, as demonstrated a decade ago by the Chelyabinsk event. Thus, their characterization is of utmost importance, and helps shed the light on why some events are more destructive than others. In addition to producing a spectacular display in the sky, fireballs and bolides are also capable of generating shockwaves. A by-product of shockwaves is a low frequency (< 20 Hz) acoustic wave, or infrasound, which should carry some information about the source, such as its energy deposition. Acoustic sensing using infrasound arrays around the globe has gained the momentum over the last decade due to its capability to detect bolides and help estimate their energy deposition irrespective of time of day or cloud coverage. However, even though infrasound experiences very little attenuation which in turn facilitates its propagation over vast distances, it is still poorly known which parameters related to bolides can be reliably extracted based on infrasound records alone. In this work, we embark on an endeavor to probe this question. We leverage the JPL Center for Near Earth Object Studies (CNEOS) database of nearly 1,000 fireballs detected by the US government sensors alongside other sources of ground truth to identify suitable bolide events to serve as our case study events. The criteria include detections by more than one infrasound station, and the existence of well-characterized source parameters obtained through other means (e.g., optical). We will present the analyses of infrasonic signals from these events and discuss feasibility of inferring bolide parameters through infrasound records alone, when no other quantifiable ground truth is available.

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA000352.

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