Letter to the Editor

Detection of small fresh craters on the Moon

Linking fresh craters to their lunar impact flash events

¹ Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris, France
² Abersytwyth University, Department of Physics, Aberystwyth SY23 3FL, UK
³ Université Côte d’Azur, CNRS–Lagrange, Observatoire de la Côte d’Azur, CS 34229, F 06304 NICE Cedex 4, France
⁴ University of Leicester, School of Physics and Astronomy, University Road, LE1 7RH Leicester, UK

^⋆ Corresponding author: ds869@leicester.ac.uk

Received: 12 May 2025
Accepted: 8 June 2025

Abstract

The luminous efficiency, η, is the fraction of an impactor’s kinetic energy that is released as light. For lunar impact flashes (LIFs), this value is currently poorly constrained, with values within the literature spanning several orders of magnitude. This is in part due to a lack of ground truth data for observed LIFs where the resultant crater has been identified. We aim to form a database of LIF-linked impact craters in order to refine parameters such as η, and to validate crater scaling laws for small (D < 100 m) regimes. Using PyNAPLE, a lunar surface change-detection pipeline, we performed a systematic search to attempt to locate the resultant craters from a selection of the most energetic LIFs. These LIF-linked craters were used to compare the validity of the frequently used crater scaling laws, and formed the basis for Monte Carlo simulations to identify a more accurate value for the luminous efficiency. We found that the most accurate crater scaling laws tested were the ones of Holsapple, Öpik, and Shoemaker & Wolfe. The Monte Carlo simulations of the predicted crater size from these three scaling laws produces a value for the luminous efficiency of η = 6.0 ± 1.2 × 10⁻³.