Orbit and origin of the LL 7 chondrite Dishchii'bikoh (Arizona)

We present the description of an observation of a fireball recorded during the sunrise on July 15, 2021. Atmospheric trajectory, impact area, and heliocentric orbit were determined on the basis of three instrumental video records. The terminal part of the fireball was not instrumentally recorded due to clouds. Based on our computations, one meteorite was found in the predicted impact area by Polish searchers. The specimen was, soon after recovery, analyzed for the presence of short‐lived radionuclides and the measurement confirms a very fresh fall, coinciding with the time of the fireball event. The recovered meteorite, Antonin, is an unbrecciated L5 chondrite with shock stage S3, weathering grade W0, and bulk density of 3.42 g cm−3. Unusual for L chondrites, it contains assemblages composed of metal and two sulfides, troilite and mackinawite. We interpret these assemblages to have been formed as products of shock metamorphism and post‐shock annealing on the parent body. This suggests that the thermal and collisional history of the Antonin parent body was complex.

Section: Discussionmentioning

confidence: 94%

Analysis of the daylight fireball of July 15, 2021, leading to a meteorite fall and find near Antonin, Poland, and a description of the recovered chondrite

Shrbený

Krzesińska

Borovička

et al. 2022

“…Greenwood et al., 2020) and among published meteorite orbits where multi‐station recordings were available to estimate orbits there are 11 from this class, roughly as expected based on the 38% fraction. Only three LL chondrite falls have known orbits, namely Chelyabinsk (Borovička et al., 2013), Stubenberg (Spurny et al., 2016), and Dishchii’bikoh (Jenniskens et al., 2020). At least one instrumental fall has a mixed classification (Dingle Dell L/LL6; Anderson et al., (Forthcoming) and Innisfree may also be in this category Granvik & Brown, 2018).…”

Section: Introductionmentioning

confidence: 99%

The Golden meteorite fall: Fireball trajectory, orbit, and meteorite characterization

Brown,

McCausland,

Hildebrand

et al. 2023

The Golden (British Columbia, Canada) meteorite fall occurred on October 4, 2021 at 0534 UT with the first recovered fragment (1.3 kg) landing on an occupied bed. The associated fireball was recorded by numerous cameras permitting reconstruction of its trajectory and orbit. The fireball entered the atmosphere at a 54° angle from the horizontal at a speed of 18 km s−1. The fireball reached a peak brightness of −14, having first become luminous at a height of >84 km and ending at 18 km altitude. Analysis of the infrasonic record of the bolide produced an estimated mass of kg while modeling of the fireball light curve suggests an initial mass near 70 kg. The fireball experienced a major flare near 31 km altitude where more than half its mass was lost in the form of dust and gram‐sized fragments under a dynamic pressure of 3.3 MPa. The strength and fragmentation behavior of the fireball were similar to those reported for other meteorite‐producing fireballs (Borovička et al., 2020). Seven days after the fireball occurred, an additional 0.9 kg fragment was recovered during the second day of dedicated searching guided by initial trajectory and dark flight calculations. Additional searching in the fall and spring of 2021–2022 located no additional fragments. The meteorite is an unbrecciated, low‐shock (S2) ordinary chondrite of intermediate composition, typed as an L/LL5 with a grain density of ~3530 k gm−3, an average bulk density of 3150 kg m−3 and calculated porosity of ~10%. From noble gas measurements, the cosmic ray exposure age is 25 ± 4 Ma while gas retention ages are all >2 Ga. Short‐lived radionuclides and noble gas measurements of the pre‐atmospheric size overlap with estimates from infrasound and light curve modeling producing a preferred pre‐atmospheric mass of 70–200 kg. The orbit of Golden has a high inclination (23.5°) and is consistent with delivery from the inner main belt. The highest probability (60%) of an origin is from the Hungaria group. We propose that Golden may originate among the background S‐type asteroids found interspersed in the Hungaria region. The current collection of 18 L/LL—chondrite orbits shows a strong preference for origins in the inner main belt, suggesting multiple parent bodies may be required to explain the diversity in CRE ages and shock states.

“…Nevertheless, the recovery of a meteorite still represents an exceptional event, although in the last few years, the refinement of detection and meteoroid trajectory calculation algorithms, and the increasing coverage of the cameras at global level has resulted in a significant increase in the number of meteorites being found. Notable recent examples are the Bunburra Rockhole "anomalous" eucrite that fell in 2007 (Bland et al 2009;Benedix et al 2017a), Mason Gully in 2010 (Dyl et al 2016), Novato meteorite in 2012 (Jenniskens et al 2014), Zd' ar nad S azavou in 2014 (Kala sov a et al 2020;, Creston in 2015 (Jenniskens et al 2019), Murrili in 2015 (Bland et al 2016), Ejby in 2016 (Spurn y et al 2017b), Stubenberg in 2016 (Bischoff et al 2017), Dishchii'bikoh in 2016 (Jenniskens et al 2020), Hradec Kralove in 2016 (Spurn y et al 2017a), and Dingle Dell in 2016 (Benedix et al 2017b).…”

Section: Introductionmentioning

confidence: 99%

“…2017), Dishchii’bikoh in 2016 (Jenniskens et al. 2020), Hradec Kralove in 2016 (Spurný et al. 2017a), and Dingle Dell in 2016 (Benedix et al.…”

Section: Introductionmentioning

confidence: 99%

Cavezzo—The double face of a meteorite: Mineralogy, petrography, and geochemistry of a very unusual chondrite

Pratesi

Cecchi

Greenwood

et al. 2021

The Cavezzo meteorite, which fell on January 1, 2020, is the first meteorite detected and recovered by the Italian PRISMA Fireball Network. Two specimens, weighing 3.12 g (specimen 1) and 52.19 g (specimen 2), were collected 3 days after the bolide was observed, thanks to an effective media campaign that encouraged the involvement of local people. The two specimens of this meteorite have not only completely different lithological characteristics but also a different geochemistry and oxygen isotopic composition as well. Specimen 1 is anomalous both for the textural–structural features, varying seamlessly from chondritic to “achondritic,” and a very unusual modal mineralogy—such as the relatively high amount of olivine (63.1 vol%), plagioclase (18.2 vol%), high‐Ca pyroxene (10.3 vol%), and chlorapatite (2.1 vol%); and the unusually low content of low‐Ca pyroxene (5.8 vol%), metal (0.1 vol%), and troilite (much lesser than 0.1 vol%)—although the compositional values for olivine (Fa 24.24 mol%) and low‐Ca pyroxene (Fs 20.41 mol%) appear to be similar to those of the L chondrite group. Conversely, in specimen 2, not only the texture and the crystal chemistry but also the modal mineralogy (low‐Ca pyroxene much more abundant than high‐Ca pyroxene and occurrence of metal and sulfides) look like those of an ordinary L chondrite. The differences between the two specimens are also confirmed by geochemistry. The oxygen isotope composition of specimen 1 plots at the boundary between the H and L groups (δ17O‰ 3.250; δ18O‰ 4.736; Δ17O‰ 0.788) whereas specimen 2 plots at the boundary of the L and LL fields (δ17O‰ 3.737; δ18O‰ 4.957; Δ17O‰ 1.159). The bulk chemistry shows a different content of many minor and trace elements (including rare earth elements), such as a strong depletion of siderophile and chalcophile elements in specimen 1. The two specimens then do not contain fragments of each other, thus preventing us from classifying this “double face” meteorite as an ordinary chondrite breccia. In detail, specimen 1 can be considered a “xenolith” in which chondritic structure and igneous texture coexist without discontinuity, and therefore, it represents a previously unsampled portion of the L parent body. In summary, these findings support the classification of Cavezzo as an L5 anomalous chondrite.