Presentation #303.04 in the session “Planetary Defense: Avenging the Dinosaurs”.
Cotto-Figueroa et al. (2016) (Icarus, Vol. 277, pp. 73-77) was the first to show that chondrite strengths obey Weibull statistics. Based on suites of uniaxial compression-to-failure experiments for multiple samples, the Weibull parameter, m, was determined for a carbonaceous (Allende, CV3) and an ordinary chondrite meteorite (Tamdakht, H5). The Weibull analysis enabled us to extrapolate the laboratory measurements of meteorite strength to make predictions about the estimated strengths of asteroidal objects of similar materials, meters to tens of meters in size, i.e., large boulders on asteroids, and major atmospheric bolides. A more recent study of the Aba Panu meteorite (Rabbi et al., 2021, Cotto-Figueroa et al., 2020), an L3 ordinary chondrite that fell in 2018 over the Nigerian state of Oyo, showed that it was more homogeneous than the Allende and Tamdakht meteorites, exhibiting therefore higher strengths at meter-scales. But contrary to Tamdakht and Allende, for which the derived scale-dependence agrees with the reported fireball data, the implication from the Aba Panu study is that meter-sized L-chondrite bolides should have greater airburst strengths than other ordinary chondrites. However, the reported “L fireballs” are quite weak. The higher strength of Aba Panu is likely related to its anomalously low porosity, 3.8%, compared to the average of 9.3% for L chondrites. The question arises as to whether Aba Panu is an anomalously strong L chondrite and demonstrates the need for further chondrite studies. As such, we are undertaking repeated destructive measurements of the Viñales L6 ordinary chondrite which fell in 2019 over the Viñales Valley, a national monument in Pinar del Rio, Cuba. This study will provide insight as to whether Aba Panu is an anomalously strong L chondrite and provide the first step to test the robustness of the derived strength scale-dependence of ordinary chondrites. Understanding how mechanical properties scale with size will allow researchers to make better predictions for the outcome of NEO airbursts such as Chelyabinsk, and rocks that spacecraft will encounter on asteroid surfaces, and ultimately to the deflection and disruption of NEOs.