Traspena        42°52.27’N, 7°19.38’W

Galicia, Spain

Confirmed fall: 18 Jan 2021

Classification: Ordinary chondrite (L5)

History: (Manuel Andrade, USC) On January 18, 2021, at 00:18:56.54 UTC, an extremely bright fireball appeared in the night sky of Galiza (NW of Spain). Sonic booms were recorded at four seismic stations and inhabitants of the regions of Ancares, Sarria and Bierzo heard as well a loud sonic boom. This superbolide was instrumentally recorded from the automated observing stations of the Universidade de Santiago de Compostela in Lugo and Santiago de Compostela and these vídeos were astrometrically calibrated by Manuel Andrade. Additionally, seven videos recorded from Caldas de Reis (Pontevedra), Corullón (León), Foncebadón (León), León, Nigrán (Pontevedra), Ponferrada (León), and Toral de los Vados (León) were carefully calibrated by José Á. Docobo and Pedro P. Campo (R.M. Aller Astronomical Observatory, USC). Eloy Peña-Asensio (UAB-CSIC) and Josep M. Trigo-Rodríguez (CSIC-IEEC) participated in the fireball astrometric reduction from the Institute of Space Sciences (CSIC-IEEC). The trajectory reconstruction, the dark flight simulations and the pre-impact heliocentric orbit computation were done by Manuel Andrade (USC). In addition, Mar Tàpia (LEGEF-IEC) performed a seismic analysis using data from four seismic stations (Pontenova, Agolada, Lobios, and Calabor). The meteoroid entered the atmosphere 75 km above the Earth’s surface at a steep angle of about 77° with a velocity of 15 km/s. It stopped ablating at a height of 16 km after decelerating to 2.4 km/s. Three main flares were recorded during the 4.84-second flight and up to nine fragments were counted in the train that formed at the end of the fireball. The initial mass of meteoroid was estimated to be about 2.62 × 10^3 kg. Since the preliminary analysis of the observations of the fireball, made in the hours immediately afterwards, indicated that part of the meteoroid had survived the entry into the atmosphere and thus reached the ground in the SW of the municipality of Baralla, a search team was organized, consisting mainly of members of the Department of Applied Mathematics of the Campus of Lugo (USC), located at only 20 km from the fall zone. Despite the nationwide shutdown due to the COVID-19 pandemic, we obtained a special permission from the USC that allowed us to conduct a large number of search days in the weeks following the event. Finally, a fusion-crusted stone weighing 527 g was found by chance on March 18, 2021, by Jesús Á. Farelo in a meadow where he usually takes his cattle to graze, in the Formigueiro place, very close to the village of Traspena, in the parish of Covas (municipality of Baralla, province of Lugo).

Physical characteristics: An only meteorite with a total mass of 527 g (with a rounded brick shape of approximately 9 × 7 × 5 cm) was recovered just two months after the fireball event. There was no traces of impact except for a small nick in one corner. This is a single stone coated by black fusion crust and exhibiting several thumb-sized regmaglyphs.

Petrography: (J. Llorca, UPC, J. M. Trigo-Rodríguez, CSIC-IEEC, and J. García-Guinea, MNCN) Thin section examination shows fairly delineated chondrules set in a recrystallized groundmass. Plagioclase grains with sizes 5-40 µm. FeNi-metal, troilite and chromite observed throughout.

Geochemistry: (Jordi Llorca, UPC, and Marc Campeny, MCNB) Olivine Fa_25.5±0.6, Fe/Mn = 48.3±2.8, N = 29; low-Ca pyroxene Fs_21.3±0.5Wo_1.5±0.7, N = 28. Magnetic susceptibility (V. Villasante-Marcos, IGN) is log χ (× 10^-9 m³/kg) = 4.89.

Classification: Ordinary chondrite (L5).

Specimens: Three sections were removed from the middle part of the only recovered meteorite to be analyzed and distributed in the following way: 29 g (MNCN), 24 g (CSIC-IEEC), and 18 g (UPC). The main remaining fragment weighs 202 g and shows the most characteristic face with many thumb-sized regmaglyphs. This type specimen was given by the finder to the Museo de Historia Natural of the Universidade de Santiago de Compostela (MHNUSC) to be preserved. The second largest fragment (182 g) is deposited in the local council of Baralla.