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TOPIC: 8TA9D69
Blobrana


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Posts: 131433
Date:
Almahata Sitta meteorite
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The Almahata Sitta (Ureilite) meteorite fell in Nahr an Nil, Sudan, on the 7th October, 2008.
A total mass of 3.95 kg was recovered.

20° 44' 45"N, 32° 24' 46"E

Almahata Sitta
("Station 6" in Arabic), Nahr an Nil, Nubian Desert, Sudan
Fall: 7 October 2008, 05:46 h local time (UT+3)
Achondrite (ureilite, polymict, anomalous)
History: On October 6, 2008, a small asteroid called 2008 TC3 was discovered by the automated Catalina Sky Survey 1.5 m telescope at Mount Lemmon, Tucson, Arizona, and found to be on a collision course with Earth. Numerous astronomical observatories followed the object until it entered the Earths umbra at Oct. 7.076 UTC the next day. The astrometric position of 295 observations of 2008 TC3 over the period Oct. 6.278 to Oct. 7.063 was used to calculate the approach trajectory over the impact location in northern Sudan. The object exploded at a high ~37 km altitude over the Nubian Desert, and as a result the meteorites are spread over a large area. A search was organized by the University of Khartoum on Dec. 29, led by P. Jenniskens (SETI Institute) and M. H. Shaddad (Khartoum).
Source (PDF)



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Blobrana


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Posts: 131433
Date:
Earth-impactor 2008 TC3
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Title: Modelling collision probability for Earth-impactor 2008 TC3
Authors: Dagmara Oszkiewicz, Karri Muinonen, Jenni Virtanen, Mikael Granvik, Edward Bowell

We study the evolution of the Earth collision probability of asteroid 2008 TC3 using a short observational arc and small numbers of observations. To assess impact probability, we use techniques that rely on the orbital-element probability density function characterised using both Markov-chain Monte-Carlo orbital ranging and Monte-Carlo ranging. First, we evaluate the orbital uncertainties for the object from the night of discovery onwards and examine the collapse of the orbital-element distributions in time. Second, we examine the sensitivity of the results to the assumed astrometric noise. Each of the orbits obtained from the MCMC ranging method is propagated into the future (within chosen time bounds of the expected impact), and the collision probability is calculated as a weighted fraction of the orbits leading to a collision from the Earth. We compare the results obtained with both methods.

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Blobrana


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Posts: 131433
Date:
Almahata-Sitta meteorite
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Title: On the origin of the Almahata-Sitta meteorite and 2008TC3 asteroid
Authors: Julie Gayon-Markt, Marco Delbo, Alessandro Morbidelli, Simone Marchi

Asteroid 2008TC3 was a Near Earth Asteroid that impacted the Earth on 2008 October 7. Meteorites were produced by the break-up of 2008TC3 in the high atmosphere and at present, about 600 meteorites - called Almahata Sitta - coming from 2008TC3 have been recovered. A mineralogical study of Almahata Sitta fragments shows that the asteroid 2008TC3 was made of meteorites of different types (ureilites, H, L, and E chondrites). Understanding the origin of this body and how it was put together remain a challenge. Here we perform a detailed spectroscopical and dynamical investigation to show that the most likely source region of 2008TC3 is in the inner Main Belt at low inclination (i<8 degrees). We show that asteroids with spectroscopic classes that can be associated with the different meteorite types of Almahata Sitta are present in the region of the Main Belt that includes the Nysa-Polana family and objects of the Background at low inclination. Searching for a possible scenario of formation for 2008TC3, we show that there is little chance that 2008TC3 was formed by low velocity collisions between asteroids of different mineralogies, in the current asteroid belt. It seems more likely that the heterogeneous composition of 2008TC3 was a inherited from a time when the asteroid belt was in a different dynamical state, most likely in the very early Solar System. Because ureilites are fragments of a large, thermally metamorphosed asteroid, this suggests that the phases of collisional erosion (the break-up of the ureilite parent-body) and collisional accretion (the formation of the parent body of 2008TC3) overlapped for some time in the primordial asteroid belt.

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Blobrana


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Posts: 131433
Date:
Meteoroid 2008 TC3
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Meteorite mystery: Amino acids from same asteroid are derived from different sources

The data suggested that the parent asteroid, named 2008 TC3, contained an unexpected mixture of several types of materials originating from primitive and evolved types of asteroids. It had been produced by a succession of break ups and collision-based enlargements, had encountered temperatures greater than 1300°C during its formation, and had not been affected by water.
Some of the studies examined the presence of extraterrestrial amino acids and polycyclic aromatic hydrocarbons. The amino acids were found in a ureilite-type fragment (fragment #4), one of the rarer forms of meteoritic material, but their discovery was surprising, given the thermal history of the asteroid. Amino acids are unstable over temperatures of 500°C.
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Blobrana


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Posts: 131433
Date:
Sudan Meteorites
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Triple Asteroid Crash Created Sudan Meteorites

Meteorites that fell over Sudan in 2008 could have come from a space rock that was formed by a triple-asteroid pileup - a collision between three different types of space rocks, a new study finds.
Scientists analysed meteorite fragments that fell to Earth exactly three years ago today, on Oct. 7, 2008, and found that they contain an unusual mix of material from both primitive and evolved types of asteroids.
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Blobrana


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Posts: 131433
Date:
Meteoroid 2008 TC3
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Asteroid 2008 TC3 - Peter Jenniskens (SETI Talks)



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Blobrana


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Posts: 131433
Date:
Almahata Sitta meteorites
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Almahata Sitta meteorites could come from triple asteroid collision

Analysis of fragments of the Almahata Sitta meteorite, which landed in Sudan in 2008, has shown that the parent asteroid was probably formed through collisions of three different types of asteroids.  The meteorites are of particular interest because they contain material both primitive and evolved types of asteroids. The results will be presented at the EPSC-DPS Joint Meeting 2011 in Nantes, France, by Dr Julie Gayon-Markt on Friday 7th October.
The meteorites are fragments of the asteroid 2008 TC3, which impacted the Earth exactly three years ago on 7th October 2008.  More than 600 fragments were collected from the Nubian Desert in Sudan.  They are collectively known as Almahata Sitta, which is Arabic for "Station Six", a train station between Wadi Halfa and Khartoum near where the fragments were found.  The impact was historic because it was the first time that an asteroid was observed in space and tracked as it descended through the Earth's atmosphere.
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Blobrana


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Posts: 131433
Date:
2008 TC3
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In 2008, astronomer Richard Kowalski, using the survey's telescope atop Mount Lemmon, identified an asteroid the size of a pickup truck that was headed for Earth. It broke into pieces over a remote area of Sudan the next night, becoming the first meteorite ever predicted in advance.
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Blobrana


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Posts: 131433
Date:
Almahata Sitta Meteorite
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NASA Discovers Asteroid Delivered Assortment of Meteorites

An international team of scientists studying remnants of an asteroid that crashed into the Nubian Desert in October 2008 discovered it contained at least 10 different types of meteorites. Some of them contained chemicals that form the building blocks of life on Earth, and those chemicals were spread through all parts of the asteroid by collisions.
Chemists at Stanford University found that different meteorite types share the same distinct fingerprint of polycyclic aromatic hydrocarbons (PAHs). These complex organic molecules are distributed throughout the galaxy and form on Earth from incomplete combustion.
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Blobrana


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Posts: 131433
Date:
2008 TC3
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Jarred awake by a thunderous explosion, Abdel Moneim Magzoub sat bolt upright in his sleeping cot on the porch of Station 6, the railway stop in northern Sudan where he worked as an attendant. It was just before dawn on October 7, 2008. His heart pounding, he woke in time to see a fireball careening through the sky and explode a second time, leaving a glowing cloud. He had no idea what he had just seen.
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