NELIOTA: First temperature measurement of lunar impact flashes

TL;DR

The NELIOTA project successfully detected and analyzed lunar impact flashes, measuring their temperatures and impactor masses, providing new insights into near-Earth object impacts and their physical characteristics.

Contribution

This study introduces the first temperature measurements of lunar impact flashes using a dual-camera setup, advancing impact physics and near-Earth object monitoring.

Findings

Temperatures of impact flashes range from ~1,600 to 3,100 K.

First measurements of temperature drops in lunar impact flashes.

Impactor masses estimated between ~100 g and 50 kg.

Abstract

We report the first scientific results from the NELIOTA (NEO Lunar Impacts and Optical TrAnsients) project, which has recently begun lunar monitoring observations with the 1.2-m Kryoneri telescope. NELIOTA aims to detect faint impact flashes produced by near-Earth meteoroids and asteroids and thereby help constrain the size-frequency distribution of near-Earth objects in the decimeter to meter range. The NELIOTA setup, consisting of two fast-frame cameras observing simultaneously in the $R$ and $I-$bands, enables - for the first time - direct analytical calculation of the flash temperatures. We present the first 10 flashes detected, for which we find temperatures in the range ~1,600-3,100 K, in agreement with theoretical values. Two of these flashes were detected on multiple frames in both filters and therefore yield the first measurements of the temperature drop for lunar flashes. In addition, we compute the impactor masses, which range between ~100 g and ~50 kg.