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TOPIC: (298) Baptistina


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Russian Meteorite Sheds Light on Dinosaur Extinction Mystery

A long-standing debate about the source of the asteroid that impacted the Earth and caused the extinction of the dinosaurs has been put to rest thanks to the Chelyabinsk meteorite that disintegrated over Russia in February 2013, a new paper published in the journal Icarus shows. 
Astronomers have debated whether the dinosaur killer was linked to the breakup of a large asteroid forming the Baptistina Asteroid Family (BAF) beyond Mars, some of which ended up on Earth-crossing orbits. The asteroid impacting Earth is thought to have been dark and carbonaceous. The BAF hypothesis was bolstered by them being dark and with a spectral shape similar to carbonaceous meteorites.

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Title: Mineralogical Characterisation of Baptistina Asteroid Family: Implications for K/T Impactor Source
Authors: Vishnu Reddy, Jorge M. Carvano, Daniela Lazzaro, Tatiana A. Michtchenko, Michael J. Gaffey, Michael S. Kelley, Thais Mothé Diniz, Alvaro Alvarez Candal, Nicholas A. Moskovitz, Edward A. Cloutis, Erin L. Ryan

Bottke et al. (2007) linked the catastrophic formation of Baptistina Asteroid Family (BAF) to the K/T impact event. This linkage was based on dynamical and compositional evidence, which suggested the impactor had a composition similar to CM2 carbonaceous chondrites. However, our recent study (Reddy et al. 2009) suggests that the composition of (298) Baptistina is similar to LL-type ordinary chondrites rather than CM2 carbonaceous chondrites. This rules out any possibility of it being related to the source of the K/T impactor, if the impactor was of CM-type composition. Mineralogical study of asteroids in the vicinity of BAF has revealed a plethora of compositional types suggesting a complex formation and evolution environment. A detailed compositional analysis of 16 asteroids suggests several distinct surface assemblages including ordinary chondrites (Gaffey SIV subtype), primitive achondrites (Gaffey SIII subtype), basaltic achondrites (Gaffey SVII subtype and V-type), and a carbonaceous chondrite. Based on our mineralogical analysis we conclude that (298) Baptistina is similar to ordinary chondrites (LL-type) based on olivine and pyroxene mineralogy and moderate albedo. S-type and V-type in and around the vicinity of BAF we characterized show mineralogical affinity to (8) Flora and (4) Vesta and could be part of their families. Smaller BAF asteroids with lower SNR spectra showing only a 'single' band are compositionally similar to (298) Baptistina and L/LL chondrites. It is unclear at this point why the silicate absorption bands in spectra of asteroids with formal family definition seem suppressed relative to background population, despite having similar mineralogy.

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NASA's WISE Raises Doubt About Asteroid Family Believed Responsible for Dinosaur Extinction

Observations from NASA's Wide-field Infrared Survey Explorer (WISE) mission indicate the family of asteroids some believed was responsible for the demise of the dinosaurs is not likely the culprit, keeping open the case on one of Earth's greatest mysteries.
While scientists are confident a large asteroid crashed into Earth approximately 65 million years ago, leading to the extinction of dinosaurs and some other life forms on our planet, they do not know exactly where the asteroid came from or how it made its way to Earth. A 2007 study using visible-light data from ground-based telescopes first suggested the remnant of a huge asteroid, known as Baptistina, as a possible suspect.

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Google earth file: Asteroid (298) Baptistina.kmz (3kb, kmz)

Ephemeris

Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V
2011 09 19 000000 13 03 54.1 -08 27 00   3.049   2.155   22.4  10.3  15.9
2011 09 29 000000 13 23 13.5 -10 37 04   3.097   2.165   17.9   8.2  15.9
2011 10 09 000000 13 42 49.7 -12 43 14   3.135   2.176   13.4   6.1  15.8
2011 10 19 000000 14 02 43.1 -14 44 29   3.165   2.186    8.8   4.0  15.8
2011 10 29 000000 14 22 54.8 -16 39 55   3.186   2.197    4.5   2.0  15.7
2011 11 08 000000 14 43 24.2 -18 28 32   3.197   2.207    2.7   1.2  15.6
2011 11 18 000000 15 04 10.1 -20 09 28   3.198   2.218    6.4   2.9  15.8
2011 11 28 000000 15 25 11.3 -21 41 55   3.189   2.229   11.2   4.9  15.9
2011 12 08 000000 15 46 24.2 -23 05 09   3.170   2.240   16.1   7.0  16.0
2011 12 18 000000 16 07 44.7 -24 18 38   3.140   2.251   21.2   9.1  16.1
2011 12 28 000000 16 29 08.5 -25 22 01   3.100   2.262   26.4  11.1  16.1
2012 01 07 000000 16 50 28.2 -26 15 05   3.050   2.273   31.7  13.1  16.2
2012 01 17 000000 17 11 37.2 -26 57 57   2.991   2.284   37.1  15.0  16.2
2012 01 27 000000 17 32 27.7 -27 30 58   2.921   2.295   42.6  16.9  16.2
2012 02 06 000000 17 52 50.2 -27 54 46   2.843   2.305   48.2  18.6  16.2
2012 02 16 000000 18 12 36.0 -28 10 14   2.756   2.316   53.9  20.2  16.2
2012 02 26 000000 18 31 35.5 -28 18 34   2.662   2.326   59.8  21.6  16.2
2012 03 07 000000 18 49 37.7 -28 21 13   2.560   2.336   65.8  22.8  16.2
2012 03 17 000000 19 06 32.7 -28 19 52   2.453   2.346   72.1  23.8  16.1
2012 03 27 000000 19 22 08.6 -28 16 27   2.342   2.356   78.5  24.5  16.0
2012 04 06 000000 19 36 12.0 -28 13 03   2.227   2.365   85.3  24.9  16.0


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Research by Dr. William F. Bottke, Dr. David Vokrouhlicky and Dr. David Nesvorny suggests that the impactor believed to have wiped out the dinosaurs and other life forms on Earth 65 million years ago can been traced back to a breakup event in the main asteroid belt.
Computer modelling shows that the parent object of asteroid (298) Baptistina, which was approximately 170-kilometres in diameter with characteristics similar to carbonaceous chondrite meteorites, was disrupted 160 million years ago when it was hit by another asteroid estimated to be 60-kilometres in diameter.

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The dinosaurs fate may have been sealed by a piece of shrapnel from a cosmic collision that occurred long before the asteroid smashed into the Yucatán Peninsula 65 million years ago. Poring through a database of objects in the asteroid belt between Mars and Jupiter, scientists at the Southwest Research Institute in Boulder, Colorado, found debris from an ancient collision. In a chaotic cluster of asteroid shards, scientists glimpsed a voidevidence that part of the cluster had moved toward the inner planets, possibly sending the killer asteroid to Earth.

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A colossal collision in space 160 million years ago set the dinosaurs on the path to extinction, a study claims.
An asteroid pile-up sent debris swirling around the Solar System, including a chunk that later smashed into Earth wiping out the great beasts.
Other fragments crashed into the Moon, Venus and Mars, gouging out some of their most dominant impact craters, a US-Czech research team believes.
Its study, based on computer modelling, is reported in the journal Nature.


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The investigators also put a 70-percent probability that a four-km Baptistina asteroid hit the Moon some around 108 million years ago forming the 85-km crater Tycho.

"We are in the tail end of this shower now. Our simulations suggest that about 20 percent of the present-day near-Earth asteroid population can be traced back to the Baptistina family" - William Bottke, Southwest Research Institute, Colorado, US.

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298 Baptistina is a typical Main belt asteroid.
It was discovered by Auguste Charlois on September 9, 1890 in Nice.
Although it has an orbit similar to the Flora family asteroids, it was found to be an unrelated interloper.

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Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V      Sky Motion
h m s "/min P.A.
2007 09 05 000000 09 36 02.9 +18 13 28 2.954 2.053 21.9 10.6 15.6 1.36 109.7
2007 09 06 000000 09 38 12.5 +18 02 22 2.949 2.053 22.3 10.7 15.6 1.36 109.9
2007 09 07 000000 09 40 21.8 +17 51 12 2.945 2.052 22.7 10.9 15.6 1.36 110.0
2007 09 08 000000 09 42 30.9 +17 39 59 2.940 2.052 23.1 11.1 15.6 1.36 110.2
2007 09 09 000000 09 44 39.6 +17 28 41 2.935 2.052 23.6 11.3 15.6 1.36 110.3
2007 09 10 000000 09 46 48.0 +17 17 19 2.931 2.052 24.0 11.5 15.6 1.36 110.4
2007 09 11 000000 09 48 56.2 +17 05 53 2.926 2.052 24.4 11.7 15.6 1.36 110.5
2007 09 12 000000 09 51 04.0 +16 54 23 2.921 2.051 24.8 11.9 15.6 1.36 110.7
2007 09 13 000000 09 53 11.6 +16 42 50 2.916 2.051 25.2 12.1 15.6 1.36 110.8
2007 09 14 000000 09 55 18.8 +16 31 13 2.911 2.051 25.7 12.3 15.6 1.36 110.9
2007 09 15 000000 09 57 25.7 +16 19 32 2.906 2.051 26.1 12.5 15.6 1.36 111.0
2007 09 16 000000 09 59 32.3 +16 07 48 2.901 2.051 26.5 12.6 15.6 1.36 111.2
2007 09 17 000000 10 01 38.7 +15 56 01 2.895 2.050 26.9 12.8 15.6 1.36 111.3
2007 09 18 000000 10 03 44.7 +15 44 10 2.890 2.050 27.4 13.0 15.6 1.36 111.4
2007 09 19 000000 10 05 50.4 +15 32 16 2.885 2.050 27.8 13.2 15.6 1.35 111.5
2007 09 20 000000 10 07 55.8 +15 20 19 2.879 2.050 28.2 13.4 15.6 1.35 111.6
2007 09 21 000000 10 10 00.9 +15 08 19 2.874 2.050 28.7 13.6 15.6 1.35 111.7
2007 09 22 000000 10 12 05.7 +14 56 16 2.868 2.050 29.1 13.8 15.6 1.35 111.9
2007 09 23 000000 10 14 10.2 +14 44 10 2.862 2.050 29.5 14.0 15.6 1.35 112.0
2007 09 24 000000 10 16 14.4 +14 32 01 2.857 2.049 30.0 14.1 15.6 1.35 112.1
2007 09 25 000000 10 18 18.2 +14 19 49 2.851 2.049 30.4 14.3 15.6 1.35 112.2

Title: GASPRAS STEEP CRATER POPULATION WAS PRODUCED BY A LARGE RECENT BREAKUP IN THE MAIN ASTEROID BELT.
Authors: W.F. Bottke, D. Vokrouhlickı, C.R. Chapman, and D. Nesvornı.

Gaspra's fresh craters, which have a surprisingly steep size frequency distribution (SFD), were mostly produced by fragments from the nearby Baptistina breakup event that took place 150 Ma.
This means that Gaspra's eroded craters may provide the most useful information on the main belts time- averaged SFD for diameter D < 0.2 km asteroids.

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The extinction of the dinosaurs 65 million years ago can be traced to a collision between two monster rocks in the asteroid belt nearly 100 million years earlier, scientists report on Wednesday.
The smash drove a giant sliver of rock into Earth's path, eventually causing the climate-changing impact that ended the reign of the dinosaurs and enabled the rise of mammals -- including, eventually, us.
Other asteroid fragments smashed into the Moon, Venus and Mars, pocking their faces with mighty craters, the US and Czech researchers believe as reported by AFP.
Mixing skills in time travel, jigsaw-making and carbon chemistry, the trio carried out a computer simulation of the jostling among orbital rubble left from the building of the Solar System.
The sleuths were guided by an intriguing clue -- a large asteroid called (298) Baptistina, which shares the same orbital track as a group of smaller rocks.
Turning the clock back, the simulation found that the Baptistina bits not only fitted together, they were also remnants of a giant parent asteroid, around 170 kilometres across, that once cruised the innermost region of the asteroid belt.
Around 160 million years ago -- the best bet in a range of 140-190 million years -- this behemoth was whacked by another giant some 60 kms across.
From this soundless collision was born a huge cluster of rocks, including 300 bodies larger than 10 kms and 140,000 bodies larger than one kilometre.
The investigators also put a 70-percent probability that a four-km Baptistina asteroid hit the Moon some around 108 million years ago forming the 85-km crater Tycho.

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