Physically based alternative to the PE criterion for meteoroids

Meteoroids impacting the Earth atmosphere are commonly classified using the PE criterion. This criterion was introduced to support the identification of the fireball type by empirically linking its orbital origin and composition characteristics. Additionally, it is used as an indicator of the meteoroid tensile strength and its ability to penetrate the atmosphere. However, the level of classification accuracy of the PE criterion depends on the ability to constrain the value of the input data, retrieved from the fireball observation, required to derive the PE value. To overcome these uncertainties and achieve a greater classification detail, we propose a new formulation using scaling laws and dimensionless variables that groups all the input variables into two parameters that are directly obtained from the fireball observations. These two parameters, α and β, represent the drag and the mass-loss rates along the luminous part of the trajectory, respectively, and are linked to the shape, strength, ablation efficiency, mineralogical nature of the projectile, and duration of the fireball. Thus, the new formulation relies on a physical basis. This work shows the mathematical equivalence between the PE criterion and the logarithm of 2αβ under the same PE criterion assumptions. We demonstrate that log(2αβ) offers a more general formulation that does not require any preliminary constraint on the meteor flight scenario and discuss the suitability of the new formulation for expanding the classification beyond fully disintegrating fireballs to larger impactors including meteorite-dropping fireballs. The reliability of the new formulation is validated using the Prairie Network meteor observations. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyMM-I acknowledges the support of Aistech Space S.L. MG acknowledges the Academy of Finland project no. 325806 (PlanetS). Research at the Ural Federal University is supported by the Russian Foundation for Basic Research, project nos 18–08-00074 and 19– 05-00028 and the Act 211 of the Government of the Russian Federation, agreement no. 02.A03.21.0006. JMT-R acknowledges the support of MEC under AYA research grant PGC2018–097374-B-I00. The authors sincerely thank the reviewers for their valuable feedback that helped us to improve the paper