Ablation and breakup of large meteoroids during atmospheric entry

Baldwin, Barrett; Sheaffer, Y. S.

doi:10.1029/ja076i019p04653

Cited by 226 publications

(111 citation statements)

References 21 publications

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“…The majority of stony meteoroids fragment in the atmosphere under low dynamic pressure, probably because of the presence of internal cracks. The most important message from the Carancas event is that meteoroid strength is a unique property of each body and does not depend on size, as assumed in many models (Baldwin & Sheaffer 1971;Nemtchinov & Popova 1997;Bland & Artiemeva 2006). Ironically, the model of Hills & Goda (1993), who assumed the same strength for all bodies of the same type (50 MPa for hard stones) is applicable to Carancas.…”

Section: Discussionmentioning

confidence: 99%

The Carancas meteorite impact – Encounter with a monolithic meteoroid

Borovička¹,

Spurný²

2008

A&A

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The formation of a 13-m wide impact crater by a stony meteorite near Carancas, Peru, on September 15, 2007 was an unexpected event. Stony meteoroids usually disintegrate in the atmosphere in many pieces, each landing at low velocity. We present examples of well-observed fireballs, which have all experienced atmospheric fragmentation. Using a simple model, we find that the Carancas meteoroid may have avoided fragmentation, if its strength was 20−40 MPa; such a strength would be comparable to the tensile strength of stony meteorites, but is higher than the strength of other observed meteoroids. We conclude that Carancas was a rare example of a monolithic meteoroid that was free of internal cracks. This example demonstrates that meteoroid strength can vary significantly from case to case and does not depend on meteoroid size. We estimate that the initial size of Carancas meteoroid was 0.9−1.7 m. Our model predicts an impact velocity that was in the range 2−4 km s −1 .

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Section: Discussionmentioning

confidence: 99%

The Carancas meteorite impact – Encounter with a monolithic meteoroid

Borovička¹,

Spurný²

2008

A&A

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“…A wide range of meteor density, from 0.4 g/cm 3 up to 7 g/cm 3 , was obtained as a result (Babadzhanov 1992a(Babadzhanov ,b, 1993Novikov et al 1996). Baldwin & Sheaffer (1971) have developed the method for analyzing meteor observations data and determining the characteristics of meteor matter, including meteoroids' capability to resist destruction in the atmosphere. They developed a model of fireball fragmentation due to aerodynamic pressure.…”

Section: Introductionmentioning

confidence: 99%

Interaction of large Taurid meteoroids with the Earth's atmosphere

Коновалова

2003

A&A

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Abstract.Results of the detailed analysis of the luminosity and ablation of bright Taurid, that break up into individual pieces in the Earth's atmosphere due to the aerodynamic pressure are presented. The aim of this analysis is to determine the composition and strength of Taurids on the basis of both photographic observations with small-meteor cameras and cameras with long focal length using the method of instantaneous exposure (τ exp = 5.6 × 10 −4 s). The study was carried out by constructing the theoretical meteor light curve while taking into account its fragmentation into two or more pieces and analyzing the aerodynamic pressure on the meteoroid at the point of splitting. The bulk densities of Taurids were obtained from an analysis of the observed light curves and compared with the strength categories obtained on the basis the data of the aerodynamic pressure at the point of meteoroid splitting. Comparing the resulting values with the known strength properties of various materials lets us conclude that Taurids could be considered structurally fragile bodies that fall into the a-strength category, have a density of 2.3 to 2.8 g/cm 3 , and can be characterized as carbonaceous chondrites. We discovered a connection between observed low-frequency pulsations of brightness of the splitting Taurids and the flares of individual pieces. We suggested that the observed lateral displacement velocity of the pieces could be caused by the explosive nature of the process of Taurid meteoroid fragmentation.

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“…When smaller bodies like meteorites and cosmic dust collide with the Earth, they are slowed to terminal velocity high in the atmosphere and can deliver organics to the surface of a planet with far less degradation (Baldwin andSheaffer 1971, Fraundorf 1980). For example, while the exterior of a meteoroid suffers serious heating and ablation during atmospheric entry, the interiors of meteorites experience little or no changes in temperatures during the entire infall process because ablation removes their surface faster than heat can thermally conduct into the interior of the meteorite.…”

Section: Delivery Of Extraterrestrial Organics To the Early Earthmentioning

confidence: 99%

Photosynthesis and Photo-Stability of Nucleic Acids in Prebiotic Extraterrestrial Environments

Sandford

Bera

Lee

et al. 2014

Topics in Current Chemistry

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Laboratory experiments have shown that the UV photo-irradiation of low-temperature ices of astrophysical interest leads to the formation of organic molecules, including molecules important for biology such as amino acids, quinones, and amphiphiles. When pyrimidine is introduced in these ices, the products of irradiation include the nucleobases uracil, cytosine, and thymine, the informational sub-units of DNA and RNA, as well as some of their isomers. The formation of these compounds, which has been studied both experimentally and theoretically, requires a succession of additions of OH, NH 2 , and CH 3 groups to pyrimidine. Results show that H 2 O ice plays key roles in the formation of the nucleobases, as an oxidant, as a matrix in which reactions can take place, and as a catalyst that assists proton abstraction from intermiediate compounds. As H 2 O is also the most abundant icy component in most cold astrophysical environments, it probably plays the same roles in space for the formation of biologically relevant compounds. Results also show that although the formation of uracil and cytosine from pyrimidine in ices is fairly straightforward, the formation of thymine is not. This is mostly due to the fact that methylation is a limiting step for its formation, particularly in H 2 O-rich ices, where methylation must competes with oxidation. The relative inefficiency of the abiotic formation of thymine to that of uracil and cytosine, coupled with the fact that thymine has not been detected in meteorites are not inconsistent with the RNA world hypothesis. Indeed, a lack of abiotically produced thymine delivered to the early Earth may have forced the choice for an RNA world, in which only uracil and cytosine are needed, but not thymine.

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Ablation and breakup of large meteoroids during atmospheric entry

Cited by 226 publications

References 21 publications

The Carancas meteorite impact – Encounter with a monolithic meteoroid

The Carancas meteorite impact – Encounter with a monolithic meteoroid

Interaction of large Taurid meteoroids with the Earth's atmosphere

Photosynthesis and Photo-Stability of Nucleic Acids in Prebiotic Extraterrestrial Environments

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