52°37′15″N12°45′40″E / 52.62083°N 12.76111°E /52.62083; 12.76111
 A fragment of2024 BX1 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | Krisztián Sárneczky |
| Discovery site | Piszkéstető Stn. |
| Discovery date | 20 January 2024 |
| Designations | |
| 2024 BX1 | |
| Sar2736, Ribbeck | |
| NEO · Apollo | |
| Orbital characteristics[3] | |
| Epoch 13 September 2023 (JD 2460200.5) | |
| Uncertainty parameter 6 | |
| Observation arc | 2.49 h (150 min) |
| Aphelion | 1.833AU |
| Perihelion | 0.835 AU |
| 1.334 AU | |
| Eccentricity | 0.3740 |
| 1.54 yr (563.0 d) | |
| 246.680° | |
| 0° 38m 22.038s / day | |
| Inclination | 7.266° |
| 300.141° | |
| 243.604° | |
| Earth MOID | 0.000532 AU (79,600 km) |
| Physical characteristics | |
| 44 cm[4] | |
| Mass | 140 kg (entry mass)[4] 1.8 kg (recovered)[5] |
| 2.5888±0.0002 s[6] | |
| E-type asteroid[4] | |
| 32.795±0.353[3] 32.84[1] –14.4 (bolide maximum)[4] | |
2024 BX1, previously known under its temporary designationSar2736, was a roughly 1 metre (3 ft)asteroid ormeteoroid that entered Earth's atmosphere on 21 January 2024 00:33UTC and disintegrated as ameteor overBerlin.[2][7] The recovered fragments are known as theRibbeck meteorite.
It was discovered less than three hours before impact by Hungarian astronomerKrisztián Sárneczky atKonkoly Observatory'sPiszkéstető Station in theMátra Mountains,Hungary.[2] It was observed with the 60 centimetres (23+5⁄8 inches)Schmidt Telescope. Sárneczky first thought it was a known asteroid because it had a brightness of 18thmagnitude, but he could not find it in any catalog, so he reported it to theMinor Planet Center.[8] Thefireball was observed by the cameras of the AllSky7[9] and Fripon[10] networks.2024 BX1 is the eighth asteroid discovered before impacting Earth, and is Sárneczky's third discovery of an impacting asteroid. Before it impacted,2024 BX1 was anear-Earth asteroid on an Earth-crossingApollo-type orbit.
Thebolide was studied in June 2024. It had a steep entry of 75.6° and an entry speed of 15.2 km/s (54,720 km/h; 34,000 mph). The bolide was observed with the SDAFO atTautenburg, which took a spectrum of the bolide. The spectrum was low in iron, consistent with anenstatite-rich body (E-type asteroid). At a height of 55 kilometres (34.2 mi) the meteoroid fragmented into smaller pieces. These primary pieces then broke up again at a height of 39–29 km (24–18 mi). The size and mass were first estimated at 1 meter and 1,700 kilograms (3,748 pounds) based onalbedos ofS-type asteroids. Theradiometric measurements from theEuropean Fireball Network did however suggest a mass of about 1200 kg. Considering it was an E-type asteroid, which have higher albedos, the new estimates are 1 meter and 1,400 kilograms (3,086 pounds).[4]
First bolide remains were found four days after it entered the Earth's atmosphere.[11][12][5] Searches were conducted by theGerman Aerospace Center (DLR), the Berlin universities, members of theMeteor Working Group andmeteorite hunters. The first samples were found byPolish searchers close to the villageRibbeck (Nauen). The meteorite fragments are therefore calledRibbeck meteorites. About 200 pieces were collected, totaling about 1.8 kilograms (4.0 pounds). The largest pieces weighed 212 grams (7.5 ounces) (sample F13) and 171 grams (6.0 ounces) (sample F14).[5] First analysis by scientists of theNatural History Museum in Berlin showed that it was anaubrite, a rare group of meteorites. The results were submitted tothe Meteoritical Society in February.[13] Later analysis of the spectrum atUV–mid-infrared wavelengths also found that the sample is consistent with aubrites. It was also shown that it had similar 0.5/0.9 μm band depths when compared to434 Hungaria, hinting at a possible linkage.2024 BX1 also shows anaphelion that is consistent with the heliocentric distances of theHungaria family.[14] A study from July 2024 describe the meteorite fragments. According to this study Ribbeck is consistent with abrecciated aubrite. The researchers found that theplagioclase fragments in Ribbeck formed from coarse-grainedmagmatic rock that cooled slowly and that were fragmented byimpacts on theparent body. The albitic plagioclase content is one of the highest among all aubrites, similar to the aubrite of Bishopville (seeMeteorite fall). This causesEuropium measurements to be higher in both meteorites. The rock showed signs ofshock metamorphism andterrestrial weathering. The 4 days of weathering in the snow/melted snow gave the samples a brown color and the breakdown of sulfides gave the samples a smell ofhydrogen sulfide (rotten eggs). Some minerals (oldhamite, aCr-rich phase and aTi-rich phase) showed strong alteration, but it is unclear if this happened partially before the meteorite impact or if it is only due to weathering.[5] The researchers believe that the parent body of Ribbeck is 4.5 billion years old.[5][15] Aubrites formed very early within a few million years after the formation ofcalcium-aluminium-rich inclusions (~4.56 billion years old) and for Ribbeck ages were determined with the help ofK–Ar dating (~3.3–3.7 billion years) andUranium/Thorium-Helium dating (~2.3–2.5 billion years). These younger ages are indications for impact events on the parent body. The cosmic ray exposure (CRE) age of Ribbeck is 55–62 million years. CRE dating is a technique to determine how long a sample was exposed to space (seesurface exposure dating).[5]
| Mineral | Bischoff et al.[5] |
|---|---|
| FeO-free enstatite | 76 ±3 vol% |
| albitic plagioclase | 15.0 ±2.5 vol% |
| forsterite | 5.5 ±1.5 vol% |
| opaque phases a) Metals, includingkamacite withNickel-rich grains (taenite ortetrataenite) b)Schreibersite c) Sulfides:troilite,djerfisherite,alabandite, oldhamite, Cr-rich phase, Ti-rich phase | 3.5 ±1.0 vol% |
| nearly FeO-freediopside | traces |
| K-feldspar | traces |
| S-bearing K-feldspar-like phase | traces |
Researchers described the meteorite fragments as "cosmic pears", in remembrance of the balladHerr von Ribbeck auf Ribbeck im Havelland byTheodor Fontane.[5][15] According to the ballad Ribbeck gavepears to passing children and after his death a legendary pear tree did grow on his grave, providing children with free pears.
Seven pieces of the meteorite were exhibited at the Natural History Museum in Berlin for a few weeks in March 2024.[16][17] A 26 grams (0.92 ounces) piece discovered by Antal Igaz is exposed at the Konkoly Observatory in Hungary. A 5.3 grams (0.19 ounces) piece found by Szymon Kozłowski is on display at theAstronomical Observatory of the University of Warsaw.[17]
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