Abstract
Estimation of 26Al (half-life = 705 kyr) content at the time of meteorite fall is required to calculate the terrestrial age of meteorites using the 26Al content. Previous studies (e.g., Cressy, 1971; Hampel et al., 1980) provided empirical equations for the estimation of 26Al content in meteorites at the time of meteorite fall. However, the equations overestimate the 26Al content of howardites and eucrites, which have a high Al content (5-8%). In this study, we present a new simple empirical equation based on the relationship between 26Al content and the content of two main target elements, Al and Si, in 37 falls meteorites from various classes (one howardite, 10 eucrites, 13 diogenites, 8 chondrites, 3 ureilites, and one angrite). The equation estimates the 26Al content of howardites and eucrites at the time of meteorite fall within a 9% difference of the measured 26Al content. This difference is lower than in any other equations presented in previous literature.
