Context. The near-Earth object (NEO) 2022 EB5 is the fifth NEO found prior to entering the Earth's atmosphere. It fragmented over the Norway Sea on 2022 March 11 about two hours after being discovered by the astronomer Krisztián Sárneczky at Konkoly Observatory in Hungary. The Center for Near-Earth Object Studies (CNEOS) at NASA detected the visible radiation emitted at the time of its atmospheric entry. The Jet Propulsion Laboratory (JPL) and European Space Agency (ESA) derived its orbital elements based on observations of its pre-atmospheric orbit. Aims. This paper aims to calculate the physical properties of this NEO, in particular, the bulk strength, type of the material, albedo, size, and mass, based on observations of its peak brightness at the time of its atmospheric entry. In addition, the heliocentric elements are computed from its interaction with Earth's atmosphere and compared with those derived from observations by JPL and ESA, respectively, to evaluate the accuracy of our method. Methods. The flight equations of 2022 EB5 were inversely integrated from the peak brightness to the atmospheric boundary via the fourth-order Runge-Kutta method. A pancake model was utilized to simulate the fragmentation of the impactor. Parameters needed to complete the integration process that were unknown were set to be optimization variables and determined via a genetic algorithm. Results. The results obtained show that 2022 EB5 was most likely a C-type asteroid with a maximal bulk strength of 2 MPa, diameter of 5–6 m, cometary density, and very low albedo that is no greater than 0.025. In addition, considering the effects of the atmosphere is helpful in getting a more accurate measurement for the semi-major axis, eccentricity, and inclination, although the accuracy of orbital elements strongly depends on the accuracy of USG sensors.
An Earth-grazing asteroid can be captured into a gravitational bound orbit around Earth during its transitory atmospheric journey. Otherwise, it will either escape back to space or plunge to Earth directly. With fragmentation taken into account, we subdivide the captured and direct impact modes, expanding the above three modes into five – escaping, captured impact with and without fragmentation, direct impact with and without fragmentation. We then investigate the conditions of those various impact modes of shallow-angle impacts of small stony asteroids no larger than 100 m in diameter. Moreover, the atmospheric entry processes of captured stony asteroids are further studied. Results show that asteroids with larger diameters are easier to fragment for less deceleration due to the smaller area-mass ratio, narrowing the corridor for capture. A captured asteroid can enter the atmosphere many times, highlighting itself by a series of explosive phenomena due to the shock wave it produced during every passage. The number of revolutions before its final entry increases as the theoretical perigee altitude rises. The multi-entry phenomenon of captured impact reduces the velocity and mass of the impactor and raises the possibility of an intact landing of the object via atmospheric dissipation. The time and space intervals between each entry make it difficult to identify whether the scattered impacts come from one captured impact event or just a series of different fireballs. The long path before its final hit also increases the difficulty of predicting the exact airburst position or landing site.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.