Autor Thema: Almahata Sitta  (Gelesen 56588 mal)

Offline herbraab

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Re: Almahata Sitta
« Antwort #210 am: Januar 03, 2014, 08:53:09 Vormittag »
Danke für die Links!

Eine mögliche Flugbahn (Probability pattern of 2014 AA south and west of the Cape Verde islands. (Credit: Asteroid Initiatives, LLC))


Kleine Korrektur: Das ist keine "Flugbahn", sondern das sind die möglichen Einschlagsorte. Da die Bahnbestimmung von 2014 AA noch einige Unsicherheiten aufwies, lässt sich der Einschlagsort leider nicht genauer festlegen. Aber zumindest steht fest, dass Material, sofern etwas den Boden erreicht hat, jedenfalls in den Atlantik gefallen ist... :crying:

 :hut:
Herbert
"Daß das Eisen vom Himmel gefallen sein soll, möge der der Naturgeschichte Unkundige glauben, [...] aber in unseren Zeiten wäre es unverzeihlich, solche Märchen auch nur wahrscheinlich zu finden." (Abbé Andreas Xaverius Stütz, 1794)

Offline karmaka

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Re: Almahata Sitta
« Antwort #211 am: Januar 03, 2014, 09:25:43 Vormittag »
Richtig, Herbert, die Linie zeigt das Muster möglicher atmospheric entry locations.
Es wäre schön, wenn doch noch irgendeine Videoaufnahme des Meteors (z.B. einer Webcam eines Touristenortes an der senegalesischen Küste) gefunden werden könnte.

Der auf der metlist bereits verlinkte Sky & Telescope - Artikel fasst übrigens einige Neuigkeiten zum Fall ganz gut zusammen.

LINK

 :hut:

Martin

Offline karmaka

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Re: Almahata Sitta
« Antwort #212 am: Dezember 18, 2014, 23:45:52 Nachmittag »
Origin and history of ureilitic material in the solar system: The view from asteroid 2008 TC3 and the Almahata Sitta meteorite

Goodrich, C. A., Hartmann, W. K., O'Brien, D. P., Weidenschilling, S. J., Wilson, L., Michel, P. and Jutzi, M. (2014)

Meteoritics & Planetary Science. doi: 10.1111/maps.12401

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Offline karmaka

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Re: Almahata Sitta
« Antwort #213 am: Januar 21, 2017, 14:17:54 Nachmittag »
Ich bin gespannt auf die ersten Ergebnisse der neuen Analyse ...

Asteroid 2008 TC3 Breakup and Meteorite Fractions

Goodrich, C.; Jenniskens, P.; Shaddad, M. H.; Zolensky, M. E.; Fioretti, A. M.   

JSC-CN-38419, Conference Paper
Asteroid Comets and Meteors Conference (ACM 2017); 10-14 Apr. 2017; Montevideo; Uruguay

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"The recovery of meteorites from the impact of asteroid 2008 TC3 in the Nubian Desert of Sudan on October 7, 2008, marked the first time meteorites were collected from an asteroid observed in space by astronomical techniques before impacting. Search teams from the University of Khartoum traced the location of the strewn field and collected about 660 meteorites in four expeditions to the fall region, all of which have known fall coordinates. Upon further study, the Almahata Sitta meteorites proved to be a mixed bag of mostly ureilites (course grained, fine grained, and sulfide-metal assemblages), enstatite chondrites (EL3-6, EH3, EH5, breccias) and ordinary chondrites (H5-6, L4-5). One bencubbinite-like carbonaceous chondrite was identified, as well as one unique Rumuruti-like chondrite and an Enstatite achondrite. New analysis: The analysed meteorites so far suggest a high 30-40 percent fraction of non-ureilites among the recovered samples, but that high fraction does not appear to be in agreement with the meteorites in the University of Khartoum (UoK) collection. Ureilites dominate the meteorites that were recovered by the Sudanese teams. To better understand the fraction of recovered materials that fell to Earth, a program has been initiated to type the meteorites in the UoK collection in defined search areas. At this meeting, we will present some preliminary results from that investigation. "


Offline karmaka

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Re: Almahata Sitta
« Antwort #214 am: Februar 03, 2017, 18:41:59 Nachmittag »
Mehr zum Thema, einschließlich der Bekanntgabe des Fundes eines weiteren kohligen Chondrits unter den AhS-Funden: AhS 202.

Almahata Sitta bleibt spannend...

A Report on 63 Newly Sampled Stones of the Almahata Sitta Fall (Asteroid 2008 TC3) from the University of Khartoum Collection, Including a C2 Carbonaceous Chondrite
A. M. Fioretti, C. A. Goodrich, M. Shaddad, P. Jenniskens, M. Zolensky, I. Kohl, E. Young, D. Rumble, N. Kita, B. Turrin, G. Herzog
48th Lunar and Planetary Science Conference (2017), Abstract #1846

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Offline karmaka

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Re: Almahata Sitta
« Antwort #216 am: Januar 09, 2019, 21:29:30 Nachmittag »
Eine schöne Idee, die individuellen Streufelddaten in der MetBull-Datenbank gemeinsam zu präsentieren.  :super:

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Offline ironsforever

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Re: Almahata Sitta
« Antwort #217 am: Januar 09, 2019, 23:00:59 Nachmittag »
Top Dokumentation! Schade nur, dass es (noch) keine Bilder der Stücke über 200g  :dizzy: Gewicht gibt.

Offline karmaka

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Re: Almahata Sitta
« Antwort #218 am: Oktober 15, 2020, 20:41:42 Nachmittag »

Hoffentlich werden wir in der Zukunft noch mehr von MS-CH hören. Ich bin neugierig auf neue Analyseergebnisse.

"Finally, the MS-CH clast in Almahata Sitta has a Cr isotopic composition (ε53Cr = 0.18 ± 0.04, ε54Cr = -0.16 ± 0.07, and δ53Cr = -0.11 ± 0.05 ‰) that is consistent (within error) with it being an R chondrite-like clast.""

Mass-independent and mass-dependent Cr isotopic composition of the Rumuruti (R) chondrites: Implication for their origin and their significance for planet formation (15.10.2020)

Ke Zhu, Frédéric Moynier, Martin Schiller, Conel M. O'D. Alexander, Jean-Alix Barrat, Addi Bischoff, Martin Bizzarro

Offline Wunderkammerad

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Re: Almahata Sitta
« Antwort #219 am: Oktober 15, 2020, 23:50:33 Nachmittag »
Rumuruti also auch noch? Was ist da eigentlich nicht drin?

Und wie muss man sich das vorstellen? Ist da irgendein Felsen so eben mal durch den Belt getingelt, immer mal wieder angehutzt, und irgendwann ist alles beieinander?

Sehr merkwürdiger Meteorit.

Offline Impakt

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Re: Almahata Sitta
« Antwort #220 am: Dezember 27, 2020, 20:55:29 Nachmittag »
Sieh so auf unseren Planeten wie wir auf andere schauen!

Offline karmaka

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Re: Almahata Sitta
« Antwort #221 am: Mai 14, 2022, 11:01:39 Vormittag »
Eure spannende Gratislektüre für dieses Wochenende.  :super:

Asteroid 2008 TC3, not a polymict ureilitic but a polymict C1 chondrite parent body? Survey of 249 Almahata Sitta fragments

Addi Bischoff, Lukas Bannemann, Stephan Decker, Samuel Ebert, Siegfried Haberer, Ursula Heitmann, Marian Horstmann, Kerstin I. Klemm, Ann-Kathrin Kraemer, Sarah Lentfort, Markus Patzek, Jakob Storz, Mona Weyrauch

MAPS
Version of Record online: 14 May 2022

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"On October 7, 2008, the asteroid 2008 TC3 exploded as it entered the Earth’s atmosphere, producing significant dust (in the atmosphere) and delivering thousands of stones in a strewn field in Sudan, collectively known as the Almahata Sitta (AhS) stones. About 600 fragments were officially recovered in 2008 and 2009. Further rocks were collected since the fall event by local people. From these stones, 249 were classified at the Institut für Planetologie in Münster (MS) known as MS-xxx or MS-MU-xxx AhS subsamples. Most of these rocks are ureilitic in origin (168; 67%): 87 coarse-grained ureilites, 60 fine-grained ureilites, 15 ureilites with variable texture/mineralogy, four trachyandesites, and two polymict breccias. We identified 81 non-ureilitic fragments, corresponding to 33% of the recovered samples studied in Münster. These included chondrites, namely 65 enstatite chondrites (43 EL; 22 EH), 11 ordinary chondrites (OC), one carbonaceous chondrite, and one unique R-like chondrite. Furthermore, three samples represent a unique type of enstatite achondrite. Since all AhS stones must be regarded as individual specimens independent from each other, the number of fresh ureilite and enstatite chondrite falls in our meteorite collections has been increased by several hundred percent. Overall, the samples weigh between <1 and 250?g and have a mean mass of ~15?g. If we consider—almost 15?years after the fall—the mass calculations, observations during and after the asteroid entered the atmosphere, the mineralogy of the C1 stones AhS 91A and AhS 671, and the experimental work on fitting the asteroid spectrum (e.g., Goodrich et al., 2019; Jenniskens et al., 2010; Shaddad et al., 2010), the main portion of the meteoroid was likely made of the fine-grained (carbonaceous) dust and was mostly lost in the atmosphere. In particular, the fact that C1 materials were found has important implications for interpreting asteroid 2008 TC3's early spectroscopic results. Goodrich et al. (2019) correctly suggested that if scientists had not recovered the “water-free” samples (e.g., ureilites, enstatites, and OC) from the AhS strewn field, 2008 TC3 would have been assumed to be a carbonaceous chondrite meteoroid. Considering that the dominating mass of the exploding meteoroid consisted of carbonaceous materials, asteroid 2008 TC3 cannot be classified as a polymict ureilite; consequently, we state that the asteroid was a polymict carbonaceous chondrite breccia, specifically a polymict C1 object that may have formed by late accretion at least 50–100?Ma after calcium–aluminum-rich inclusions."
« Letzte Änderung: Mai 14, 2022, 11:19:14 Vormittag von karmaka »

Offline Sikhote

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Re: Almahata Sitta
« Antwort #222 am: Mai 14, 2022, 13:38:41 Nachmittag »
 :super:
 :winke: Sigrid

Offline Dirk

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Re: Almahata Sitta
« Antwort #223 am: Mai 14, 2022, 16:45:41 Nachmittag »
Danke für den link, Martin!!!

Sehr interessant.  :super:

Dirk

Offline karmaka

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Re: Almahata Sitta
« Antwort #224 am: August 05, 2022, 09:27:35 Vormittag »
Hier wieder eine spannende Urlaubslektüre für euch:

Bolide fragmentation: What parts of asteroid 2008 TC3 survived to the ground?

Peter Jenniskens, Darrel Robertson, Cyrena A. Goodrich, Muawia H. Shaddad, Ayman Kudoda, Anna M. Fioretti, Michael E. Zolensky

MAPS (4.8.22)

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