Description
Renchen 48°35’17.9988’’N, 8°0’00.00’’E
Baden-Wurttemberg, Germany
Confirmed fall: 10 July 2018
Classification: Ordinary chondrite (L5-6)
History: (Pavel Spurný, CzAS). A -13.4 maximum absolute magnitude bolide was observed by many of eyewitnesses, mainly over western Germany, eastern France, Belgium, Netherlands, Luxembourg, and Switzerland, and recorded photographically and photoelectrically by instruments of the Czech and German parts of the European Fireball Network on July 10, 2018, at 21:29:49-53 UT. Based on these instrumental data, precise results on atmospheric trajectory, heliocentric orbit and fragmentation history were quickly determined. From this analysis (done at CzAS), it was evident that this event terminated with a multiple meteorite fall in Baden-Württemberg, close to the Rhine river. The impact area for a possible range of meteorite masses was thus modeled and sent to a German colleague (Dieter Heinlein) shortly after the fall. As a result, all of the meteorites were found in the predicted location for a given mass during dedicated searches.
Physical characteristics: (D. Heinlein). A total mass of 999 g was recovered within the predicted fall site. The first meteorite (12 g) was discovered two weeks after the fall. The largest meteorite fragment had a mass of 955 g and was found in a field. close to a small impact pit. Two of the meteorites (5 and 6 g) were caught by a hail net covering a fruit plantation.
Petrography: (M. Patzek and A. Bischoff, IfP): Based on the study of the thin sections, Renchen is brecciated. Highly recrystallized fragments (type 6) coexist with areas showing a chondritic texture (type 5) and fragments of impact melt. Olivine shows weak mosaicism indicating shock stage S4. Opaque phases include metals (kamacite, taenite), troilite, and chromite. Other accessory phases include Cl-apatite and merrillite. Several shock veins cross the meteorite.
Geochemistry: (M. Patzek and A. Bischoff, IfP): The mean composition of olivine is Fa26.0±0.5 with a compositional range of Fa24.6-27.1 (n=59). The low-Ca pyroxene has a mean composition of Fs21.9±0.4Wo1.4±0.3 (n= 21), varying between Fs21.1-22.6. Mean plagioclase is An9.8±0.6Or3.9±2.6 (n= 10; range An8.6-10.7). O-isotopes (A. Pack; UGött): The mean oxygen isotope composition of two analyzed fragments is: δ17O = 3.63‰, δ18O = 4.74‰, Δ17O = 1.12‰ (relative to a reference line with a slope of 0.5305). The data are consistent with those of other L chondrites.
Classification: L chondrite breccia (L5-6, S4, W0)
Specimens: Type Specimens: 20.9 g, IfP; the main masses are with the finders.
