Roberto Gorelli points our attention at a recently published meteor related paper:

The Winchcombe Fireball—that Lucky Survivor

This article has been submitted for publication by Sarah McMullan, Denis Vida, Hadrien A. R. Devillepoix, Jim Rowe, Luke Daly, Ashley J. King, Martin Cupák, Robert M. Howie, Eleanor K. Sansom, Patrick Shober, Martin C. Towner , Seamus Anderson, Luke McFadden, Jana Horák, Andrew R. D. Smedley, Katherine H. Joy, Alan Shuttleworth, Francois Colas, Brigitte Zanda, Aine C. O’Brien, Ian McMullan, Clive Shaw, Adam Suttle, Martin D. Suttle, John S. Young, Peter Campbell-Burns, Richard Kacerek, Richard Bassom, Steve Bosley, Richard Fleet, Dave Jones, Mark McIntyre, Nick James, Derek Robson, Paul Dickinson, Philip A. Bland, and Gareth S. Collins.

Abstract: On February 28, 2021, a fireball dropped ∼ 0.6 kg of recovered CM2 carbonaceous chondrite meteorites in South-West England near the town of Winchcombe. We reconstruct the fireball’s atmospheric trajectory, light curve, fragmentation behaviour, and pre-atmospheric orbit from optical records contributed  by five networks. The progenitor meteoroid was three orders of magnitude less massive (∼ 13 kg) than any previously observed carbonaceous fall. The Winchcombe  meteorite survived entry because it was exposed to a very low peak atmospheric dynamic pressure (∼ 0.6 MPa) due to a fortuitous combination of entry parameters,  notably low velocity (13.9 km s^−1). A near-catastrophic fragmentation at ∼ 0.07 MPa points to the body’s fragility. Low entry speeds which cause low peak dynamic pressures are likely necessary conditions for a small carbonaceous meteoroid to survive atmospheric entry, strongly constraining the radiant direction to the general antapex direction. Orbital integrations show that the meteoroid was injected into the near-Earth region ∼ 0.08 Myr ago and it never had a perihelion distance smaller than ∼ 0.7 AU, while other CM2 meteorites with known orbits approached the Sun closer (∼ 0.5 AU) and were heated to at least 100 K higher temperatures. 

You can download this paper for free: (22 pages).


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