Chicxulub impactor

Sketch of the gravity anomaly map of the Chicxulub crater area. Red and yellow are gravity highs, green and blue are gravity lows, white indicates sinkholes, or "cenotes", and the shaded area is the Yucatan Peninsula.^[1][2]

Artistic rendition of the Chicxulub impactor striking ancient Earth, with Pterosaur observing.

The Chicxulub impactor (/ˈtʃiːkʃəluːb/ CHEEK-shə-loob), also known as the K/Pg impactor and (more speculatively) as the Chicxulub asteroid, was an asteroid 10 to 15 kilometres in diameter^[3][4] which struck the Earth at the end of the Cretaceous, approximately 66 million years ago,^[5] creating the Chicxulub crater. It impacted a few miles from the present-day town of Chicxulub in Mexico, after which the impactor and its crater are named. Because the estimated date of the object's impact and the Cretaceous–Paleogene boundary (K–Pg boundary) coincide, there is a scientific consensus that its impact was the Cretaceous–Paleogene extinction event which caused the death of most of the planet's non-avian dinosaurs and many other species.^[6][7]

The impactor's crater is just over 177 kilometers in diameter,^[8] making it the third largest known impact crater on Earth.

Parent body

There are several competing models for the impactor's origin and its relationship to other asteroids that still exist in the Solar System. In September 2007, William F. Bottke, David Vokrouhlický, and David Nesvorný proposed an origin for the impactor in an article published in Nature. This argued that a collision in the asteroid belt 160 million years ago resulted in the Baptistina family of asteroids, the largest surviving member of which is 298 Baptistina. They proposed that the Chicxulub impactor was an asteroid member of this group, referring to the large amount of carbonaceous material present in microscopic fragments of the object, suggesting that it was a member of a rare class of asteroids called carbonaceous chondrites, like Baptistina. According to Bottke, the Chicxulub impactor was a fragment of a much larger parent body about 170 km (110 mi) across, with the other impacting body being around 60 km (40 mi) in diameter. However, in 2011 new data from the Wide-field Infrared Survey Explorer revised the date of the collision which created the Baptistina family to about 80 million years ago, casting doubt on the theory, as typically the process of resonance and collision of an asteroid takes many tens of millions of years.^[9]

Other work has associated the asteroid P/2010 A2, a member of the Flora family of asteroids, as a possible remnant cohort of the Chicxulub impactor.^[10]

See also

• Alvarez hypothesis
• Timeline of Cretaceous-Paleogene extinction event research

Notes and references

Impact cratering on Earth • Impact crater
Lists	Worldwide Africa Antarctica Asia Australia Europe North America South America By country
Confirmed ≥20 km diameter	Acraman Amelia Creek Araguainha Beaverhead Boltysh Carswell Charlevoix Chesapeake Bay Chicxulub Clearwater East & West Gosses Bluff Haughton Kamensk Kara Karakul Keurusselkä Lappajärvi Logancha Manicouagan Manson Mistastin Mjølnir Montagnais Morokweng Nördlinger Ries Obolon' Popigai Presqu'île Puchezh-Katunki Rochechouart Saint Martin Shoemaker Siljan Ring Slate Islands Steen River Strangways Sudbury Tookoonooka Tunnunik Vredefort Woodleigh Yarrabubba
Topics	Alvarez hypothesis Breccia Coesite Complex crater Cretaceous–Paleogene boundary Cryptoexplosion Ejecta blanket Impact crater Impact structure Impactite Late Heavy Bombardment Lechatelierite Meteorite Moldavite Ordovician meteor event Planar deformation features Shatter cone Shock metamorphism Shocked quartz Stishovite Suevite Tektite
Research	Baldwin, Ralph Belknap Barringer, Daniel Barringer Medal Chao, Edward C T Dietz, Robert S Hartmann, William K Melosh, H Jay Ryder, Graham Schultz, Peter H Shoemaker, Eugene Earth Impact Database Impact Field Studies Group Lunar and Planetary Institute Traces of Catastrophe

Coordinates: 21°24′N 89°31′W / 21.400°N 89.517°W / 21.400; -89.517