Ådalen (prov.) iron meteorite of 7 November 2020 (21:27:00 UT) bolide found near Ådalen, Enköping Municipality, Uppsala County, Sweden

Last update: 23 February 2021

The regmaglypted ‘Ådalen’ (prov.) iron meteorite with its velvety fusion crust. Photo: Andreas Forsberg and Anders Zetterqvist

On 23 February it was announced that on 5 December 2020 a ~14-kilogram iron meteorite (30 centimeters long) was found by Andreas Forsberg, geologists from Stockholm, about 70 meters away from the location of the rock mark and the damaged roots in the ground, which were discovered by geologist Anders Zetterqvist on 16 November. The meteorite is reported to have bounced against a boulder and then a flat rock outcrop on the ground, before it became embedded into the soil surrounded by roots and moss. Forsberg says he saw something ‘glowing’ well embedded and sticking up from the mossy ground, which attracted his attention. Immediately after the find he didn’t dig it out but covered it with moss, went back to his car and called Zetterqvist who convinced him to dig out ‘the find of his lifetime’ immediately. The mass was larger than expected. The meteorite shows signs (a large crack and impact marks) of its collision with the big boulder. It is considered to be the ‘main mass’ of the fall, but other masses (with an approximate total weight equal to that of the found specimen) might be found in the area. The meteorite has been handed over to the Swedish Museum of Natural History, on loan for a year. Forsberg apparently would like it to be exhibited there and hopes to get a reasonable compensation. The Swedish Museum of Natural History equally hopes to acquire the meteorite for its collection.

Before, on 26 January, the Uppsala University and the Swedish Royal Museum of Natural History reported that ‘following tips of meteorite collectors’ on 17 November the mineralogist Jörgen Langhof, Curator of minerals at the Swedish Royal Museum of Natural History, found ~20 small nickel-containing fragments (1-6 mm) of a meteorite which is thought to have fallen at ~21:27 UT on 7 November 2020. The fragments were reportedly found with a magnet on the mossy ground near the village Ådalen, north of Fjärdhundra, Sweden, about 2.8 kilometers (on the ground) northeast of the calculated end of the bolide’s luminous trail. The fragments were reportedly found within a radius of 10 meters around a boulder which is thought to have been hit by a hard object and a pit with damaged tree roots which is supposed to have be caused by the impact of a ‘fist-sized object’. The place with the roots and the rock had reportedly been found on 16 November by one of the ‘hobby meteorite hunters’, Anders Zetterqvist, who then told Langhof about it. According to Langhof, after his arrival at the site he searched the area around the pit for merely five minutes while using a neodymium magnet before he found the fragments.

If a short terrestrial age of the meteorite (which, we believe, must be determined by properly measuring short-lived isotopes of this specimen very soon) confirms its connection to the bolide of 7 September 2020, it will be the first known meteorite fall in Sweden since 1954.

The meteorite ‘in situ’ on 5 December 2020. Photo: Andreas Forsberg

Andreas Forsberg and Anders Zetterqvist presenting the meteorite. Photo: Andreas Forsberg and Anders Zetterqvist

The probable path of the bouncing meteorite mass. Photo: Anders Zetterqvist

Three fragments. Photo: Naturhistoriska riksmuseet

Photo: Naturhistoriska riksmuseet

Press

LINK Naturhistoriska riksmuseet – Press release (23 February 2021)

LINK Naturhistoriska riksmuseet (23 February 2021)

LINK (23 February 2021)

LINK (Uppsala universitet, 26 January 2021)

LINK (Naturhistoriska riksmuseet, 26 January 2021)

The bolide

The preatmospheric orbit

Trajectory calculations (Norsk meteornettverk)

The preatmospheric orbit (orbit elements: perihelion distance: 0.898 AU, eccentricity: 0.546, inclination: 15.0°, knot length: 225.6°, perihelion argument: 222.7°, mean anomaly: 348.8°

Video recordings of the bolide

Video from Larvik, Norway. Video: Norsk meteornettverk

Bolide (00:03-) and detonation booms (00:33-). Video: biancoczt1 (16 November 2020)

Bolide (00:03-) and detonation booms (00:35-). Video: biancoczt1 (16 November 2020)

Video from Tampere, Finland. Video: kakuure

Video from Merikarvia, Finland

Video from Västerås, Schweden. Video: Cadde News

NORSAR’s infrasound station in Løten registered clear signales in an easterly direction (azimuth 111) 22:48 (21:48 GMT) 2020