A Fireball and Potentially Hazardous Binary Near-Earth Asteroid (164121) 2003 YT1

Abstract

Abstract We present a fireball detected in the night sky over Kyoto, Japan on UT 2017 April 28 at by the SonotaCo Network. The absolute visual magnitude is = −4.10 ± 0.42 mag. Luminous light curves obtain a meteoroid mass of m = 29 ± 1 g, corresponding to the size of a s = 2.7 ± 0.1 cm. Orbital similarity assessed by D-criterions (see D SH = 0.0079) has identified a likely parent, the binary near-Earth asteroid (164121) 2003 YT1. The suggested binary formation process is a Yarkovsky–O’Keefe–Radzievskii–Paddack-driven rotational disintegration. The asynchronous state indicates the age of <104 yr, near or shorter than the upper limit to meteoroid stream lifetime. We examine potential dust production mechanisms for the asteroid, including rotational instability, resurfacing, impact, photoionization, radiation pressure sweeping, thermal fracture, and sublimation of ice. We find some of them capable of producing the meteoroid-scale particles. Rotational instability is presumed to cause mass shedding, in consideration of the recent precedents (e.g., asteroid (6478) Gault), possibly releasing millimeter–centimeter scale dust particles. Impacts by micrometeorites with a size ≃1 mm could be a trigger for ejecting the centimeter-sized particles. Radiation pressure can sweep out the millimeter-sized dust particles, while not sufficient for the centimeter-sized. The other mechanisms are unprovable or unidentified. The feasibility in the parental aspect of 2003 YT1 is somewhat reconciled with the fireball observation, yielding an insight into how we approach potentially hazardous objects.