Luminous efficiency based on FRIPON meteors and limitations of ablation models

¹ University of Oldenburg, Division for Medical Radiation Physics and Space Environment, Germany
e-mail: esther.drolshagen@uni-oldenburg.de; theresa.ott@uni-oldenburg.de
² European Space Agency, ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
³ Chair of Astronautics, TU Munich, Germany
⁴ IMCCE, Observatoire de Paris, PSL Research University, CNRS UMR 8028, Sorbonne Université, France
⁵ Institut de Minéralogie, Physique des Matériaux et Cosmochimie (IMPMC), Muséum National d’Histoire Naturelle, CNRS UMR 7590, Sorbonne Université, 75005 Paris, France
⁶ FRIPON (Fireball Recovery and InterPlanetary Observation) and Vigie-Ciel Team, France
⁷ GEOPS-Géosciences, CNRS, Université Paris-Saclay, 91405, Orsay, France
⁸ Service Informatique Pythéas (SIP) CNRS - OSU Institut Pythéas – UMS 3470, Marseille, France
⁹ Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France
¹⁰ INAF - Osservatorio Astrofisico di Torino - Via Osservatorio 20, 10025 Pino Torinese, TO, Italy
¹¹ Astronomical Institute of the Romanian Academy, Bucharest, 040557, Romania
¹² MOROI (Meteorites Orbits Reconstruction by Optical Imaging) Astronomical Institute of the Romanian Academy, Bucharest, Romania
¹³ SCAMP (System for Capture of Asteroid and Meteorite Paths), FRIPON, UK
¹⁴ Planétarium Rio Tinto Alcan/Espace pour la vie, Montréal, Québec, Canada
¹⁵ Réseau DOME, (Détection et Observation de Météores/Detection and Observation of Meteors), Canada
¹⁶ SPMN (SPanish Meteor Network), FRIPON, Spain
¹⁷ Institute of Space Sciences (CSIC), Campus UAB, Facultat de Ciències, 08193 Bellaterra, Barcelona, Catalonia, Spain
¹⁸ Institut d’Estudis Espacials de Catalunya (IEEC), 08034 Barcelona, Catalonia, Spain
¹⁹ FRIPON-Belgium.
²⁰ Royal Belgian Institute for Space Aeronomy, Brussels, Belgium
²¹ Natural History Museum, Burgring 7, 1010 Vienna, Austria
²² FRIPON-Austria.
²³ Università degli Studi di Torino, Dipartimento di Fisica, Via Pietro Giuria 1, 10125 Torino, TO, Italy
²⁴ INAF – Osservatorio di Astrofisica e Scienza dello Spazio Via Piero Gobetti 93/3, 40129 Bologna, BO, Italy
²⁵ INAF – Istituto di Astrofisica e Planetologia Spaziali Via del Fosso del Cavaliere 100, 00133 Roma, RM, Italy
²⁶ CNR – Istituto di Fisica Applicata Nello Carrara, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy
²⁷ Space sciences, Technologies Astrophysics Research (STAR) Institute, Université de Liège, Liège 4000, Belgium
²⁸ Universitat degli Studi di Firenze - Dipartimento di Scienze della Terra, Via Giorgio La Pira, 4, 50121 Firenze, FI, Italy
²⁹ Natural History Museum, Cromwell Road, London, UK
³⁰ Dep. Fisica Aplicada I, Escuela de Ingeniera de Bilbao, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, 48013 Bilbao, Spain
³¹ Aula EspaZio Gela, Escuela de Ingeniera de Bilbao, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, 48013 Bilbao, Spain
³² FRIPON-Netherlands, European Space Agency, SCI-SC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
³³ Osservatorio Astronomico del Righi, Via Mura delle Chiappe 44R, 16136 Genova, GE, Italy
³⁴ Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Catalonia, Spain

Received: 22 December 2020
Accepted: 1 April 2021

Abstract

Context. In meteor physics, the luminous efficiency τ is used to convert the meteor’s magnitude to the corresponding meteoroid’s mass. However, a lack of sufficiently accurate verification methods or adequate laboratory tests mean that discussions around this parameter are a subject of controversy.

Aims. In this work, we aim to use meteor data obtained by the Fireball Recovery and InterPlanetary Observation to calculate the luminous efficiencies of the recorded meteors. We also show the limitations of the methods presented herein.

Methods. Deceleration-based formulas were used to calculate the masses of the pre-atmospheric meteoroids. These can in turn be compared to the meteor brightnesses to assess the luminous efficiencies of the recorded objects. Fragmentation of the meteoroids is not considered within this model. Good measurements of the meteor deceleration are required.

Results. We find τ-values, as well as the shape change coefficients, of 294 meteors and fireballs with determined masses in the range of 10⁻⁶–100 kg. The derived τ-values have a median of τ_median = 2.17%. Most of them are of the order of 0.1–10%. We present how our values are obtained, compare them with data reported in the literature, and discuss several methods. A dependence of τ on the pre-atmospheric velocity of the meteor, v_e, is noticeable with a relation of τ = 0.0023⋅v_e^2.3. Furthermore, a dependence of τ on the initial meteoroid mass, M_e, is found with negative linear behaviour in log–log space: τ = 0.48⋅M_e^−0.47.

Conclusions. The higher luminous efficiency of fast meteors could be explained by the higher amount of energy released. Fast meteoroids produce additional emission lines that radiate more efficiently in specific wavelengths due to the appearance of the so-called second component of higher temperature. Furthermore, the negative dependence of τ on M_e implies that the radiation of smaller meteoroids is more efficient. The results of this study also show the limitations of the ablation-based model for the determination of the luminous efficiency.