Very low strengths of interplanetary meteoroids and small asteroids

Abstract

Abstract-We have assembled data on 13 cases of meteorite falls with accurate tracking data on atmospheric passage. In all cases, we estimate the bulk strength of the object corresponding to its earliest observed or inferred fragmentation in the high atmosphere, and can compare these values with measured strengths of meteorites in the taxonomic class for that fall. In all 13 cases, the strength corresponding to earliest observed or inferred fragmentation is much less than the compressive or tensile strength reported for that class of stony meteorites. Bulk strengths upon atmospheric entry of these bodies are shown to be very low, 0.1 to approximately 1 MPa on first breakup, and maximal strength on breakup as 1-10 MPa corresponding to weak and ''crumbly'' objects, whereas measured average tensile strength of the similar meteorite classes is about 30 MPa. We find a more random relation between bulk sample strength and sample mass than is suggested by a commonly used empirical power law. We estimate bulk strengths on entry being characteristically of the order of 10 )1 -10

Spectra and physical properties of Taurid meteoroids

“…Both of these quantities can be easily measured from the observational data and the atmospheric model, but the determination of the fragmentation height is often difficult. Various methods can be applied for this purpose, depending on the type of available data and the type of meteoroid fragmentation (Popova et al, 2011). The fragmentation heights of the Taurid meteoroids presented here were determined from meteor light curves.…”

Survival of the impactor during hypervelocity collisions – I. An analogue for low porosity targets

“…Several literature sources give the compressive and tensile strength for a series of meteorites, however the number that has been studied is very limited. Popova et al (2011) summarises data from several meteorites, giving the ranges of compressive and tensile strengths to be 20 -450 MPa and 2 -62 MPa for L ordinary chondrites, and 77 -327 MPa and 26 -42 MPa for H ordinary chondrites. However, the calculated bulk strengths during entry of similar type meteoroids into the Earth's atmosphere are much lower than the above-quoted strengths.…”

Are some meteoroids rubble piles?

“…three orders of magnitude higher than the strength of rubble piles. Although not a rubble pile, the bulk strength of Benešov was lower than of other meteorite dropping meteoroids (Popova et al 2011). The initial disruption was severe -the largest fragments were of only 1 -2% of the original mass (∼ 25% in terms of size).…”

“…It occurs when the dynamic pressure, p = ρv 2 (ρ is atmospheric density and v is meteoroid velocity) exceeds meteoroid strength. While the tensile strength of monolithic rocks (meteorites) exceeds 30 MPa, the strengths of meteoroids inferred from their atmospheric fragmentations was found to be in the range 0.1 -10 MPa (Popova et al 2011). The lowered strength is likely caused by internal fractures.…”