Novo Mesto EPSC abstract published

Vida et al. have published an abstract (PDF) to the European Planetary Science Congress (EPSC) of 2021 where they give the orbital parameters for Novo Mesto, an L5 chondrite with a photographic orbit which fell in Slovenia in February 2020. This is enough for inclusion in our list of published meteorite orbits, and a corresponding entry has been added. In total, there are now 38 meteorites with published orbital elements derived from photographic documentation.

To answer a related frequently asked question, I am aware that there are a number of recently fallen meteorites for which it is known that orbital elements were determined based on photographic documentation of the entry fireball – however, the orbital elements for these meteorite orbits are not currently available in the scientific literature because the authors chose not to add them to an abstract where they announced the publication of an orbit solution, or just haven’t published them yet in a regular journal article. If you find an abstract or article reporting orbital elements for a meteorite currently not listed, please let me know. /m4

Motopi Pan / asteroid 2018 LA

A new meteorite with associated orbit has been added to the table: Motopi Pan. Although officially classified as a howardite (in the MetBull database), it is a complex HED breccia with howardite, cumulate and basaltic eucrites, as well as diogenite lithologies, as the authors write in an article published online today in MAPS (Jenniskens et al., 2021). This is only the second time (the first was Almahata Sitta in 2008) that a meter-scale asteroid was found to be on a collision course with Earth only a few hours prior to impact (the asteroid was named 2018 LA), observed as a meteor when it entered the Earth’s atmosphere, and meteorites recovered afterwards, this time in Botswana. Because of the longer observation arc, the orbit is much better constrained compared to a typical “meteorite-with-orbit” fall. The orbit strongly suggests the meteoroid was delivered via the nu-6 resonance from the large asteroid Vesta. From the combination of ejection age (= cosmic-ray exposure age, ca. 22 Ma) and shock-reset age in phosphates, Jennsikens et al. (2021) even suggest that the source crater of the impact might be Rubria, in the Venenaia impact basin on Vesta.

Full disclosure: I am a co-author on the paper. /m4

New paper out: Dishchii’bikoh in MAPS

A new meteorite with an orbit has been published in Meteoritics & Planetary Science (MAPS): Dishchii’bikoh. It is a rare LL7 chondrite which fell near the city of Cibecue in Arizona / USA, and takes its name as pronounced in the language of the local White Mountain Apache tribe. Several fragments of almost 80 g total mass were recovered using the weather radar footprint of the fall. The orbit of the meteorite is remarkable for being relatively short (1.13 AU semi-major axis) and steeply inclined (ca. 21° to the ecliptic). Radionuclides suggest it was a relatively large meteoroid, at R = 60-100 cm. The cosmic-ray exposure age is quite typical for an ordinary chondrite, at 11 Ma. It seems likely the meteorite derived from the Flora family of asteroids in the inner asteroid belt, similar to other recent LL chondrite falls, like Stubenberg (2016) and Chelyabinsk (2013).

Full disclosure: I am a co-author on the paper. /m4

New papers out: Žďár nad Sázavou in MAPS and Porangaba in Icarus

Spurný et al. report in a new paper in MAPS on the fireball trajectory, orbit and meteorite recovery of the Žďár nad Sázavou (L3.9) meteorite, which fell in the Czech Republic on December 9th, 2014. This is the first unequilibrated ordinary chondrite with an orbit. The orbit has been in the database since 2016 because it was published in a MetSoc (Berlin) abstract by Spurný et al., 2016, now superseded by the peer-reviewed paper. The changes in the orbital parameters given in the paper, relative to the ones given in the abstract, are marginal, but I updated the list nevertheless.

Ferus et al. report in a new paper in Icarus on the trajectory, orbit and meteorite recovery of the Porangaba (L4) meteorite, which fell in Brazil just one month after the fall of Žďár nad Sázavou, on January 9th, 2015. Using two pictures of the dust trail, as well as some security camera footage allowed the authors to derive a set of orbital parameters, albeit with a comparatively large uncertainty. But since there is a closed orbital solution (unlike, e.g., to the somewhat similar case of the 1995 St. Robert meteorite), I have added the meteorite to the database. An interesting detail: the addition of Porangaba makes 2015 the first year from which (at least) four meteorite falls with orbits are known. Compare this with the fact that it took 33 years for the first four orbits…

I have updated the fall statistics and orbit plots, which now include the most recent falls including Porangaba. /m4