Velocity Distributions among Colliding Asteroids

Bottke, W. F.; Nolan, M. C.; Greenberg, R.; Kolvoord, Robert A

doi:10.1006/icar.1994.1021

Cited by 387 publications

(337 citation statements)

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“…Variances of the change in proper a massive asteroids varied up to 23% in the four integration schemes that we used. We confirm the hypothesis of Bottke et al (1994) that encounters with highly inclined objects as (2) Pallas are indeed a minor effect because of rather high relative speed and distances at encounters between perturber and perturbee. Unexpectedly, we found a very large mean value of drift rate in proper a caused by close encounters with (10) Hygiea, σ a [1] × 10 5 = (90.8 ± 20.6) AU, and (31) Euphrosyne, σ a [1] × 10 5 = (72.9 ± 13.7) AU.…”

Section: Discussionsupporting

confidence: 87%

“…Only a very limited number of close encounters satisfied our criterion for relevance of causing a change in Δa larger than 3σ (at most, just three for the S9 simulation). The very low value of drift in proper a caused by encounters with (2) Pallas seems to confirm the hypothesis of Bottke et al (1994) that encounters with this highly inclined asteroid occur mostly at high relative speed and distances and therefore cause limited changes in proper elements. To further investigate this hypothesis, we consider the case of (31) Euphrosyne in the next sub-section.…”

Section: (2) Pallassupporting

confidence: 77%

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Chaotic diffusion caused by close encounters with several massive asteroids

Carruba

Huaman

Domingos

et al. 2013

A&A

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Context. Close encounters with (1) Ceres and (4) Vesta, the two most massive bodies in the main belt, are known to be a mechanism of dynamical mobility able to significantly alter proper elements of minor bodies, and they are the main source of dynamical mobility for medium-sized and large asteroids (D > 20 km, approximately). Recently, it has been shown that drift rates caused by close encounters with massive asteroids may change significantly on timescales of 30 Myr when different models (i.e., different numbers of massive asteroids) are considered. Aims. So far, not much attention has been given to the case of diffusion caused by the other most massive bodies in the main belt: (2) Pallas, (10) Hygiea, and (31) Euphrosyne, the third, fourth, and one of the most massive highly inclined asteroids in the main belt, respectively. Since (2) Pallas is a highly inclined object, relative velocities at encounter with other asteroids tend to be high and changes in proper elements are therefore relatively small. It was thus believed that the scattering effect caused by highly inclined objects in general should be small. Can diffusion by close encounters with these asteroids be a significant mechanism of long-term dynamical mobility? Methods. By performing simulations with symplectic integrators, we studied the problem of scattering caused by close encounters with (2) Pallas, (10) Hygiea, and (31) Euphrosyne when only the massive asteroids (and the eight planets) are considered, and the other massive main belt asteroids and non-gravitational forces are also accounted for. Results. By finding relatively small values of drift rates for (2) Pallas, we confirm that orbital scattering by this highly inclined object is indeed a minor effect. Unexpectedly, however, we obtained values of drift rates for changes in proper semi-major axis a caused by (10) Hygiea and (31) Euphrosyne larger than what was previously found for scattering by (4) Vesta. These high rates may have repercussions on the orbital evolution and age estimate of their respective families.

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Section: Discussionsupporting

confidence: 87%

Section: (2) Pallassupporting

confidence: 77%

Chaotic diffusion caused by close encounters with several massive asteroids

Carruba

Huaman

Domingos

et al. 2013

A&A

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“…At impact speeds up to 3 km/s, which occur at the lower part of the velocity distribution in the Main Belt (Bottke et al 1994; O'Brien & Sykes 2011), we observe no detectable melting of the projectile, as determined by visual observation and Raman spectroscopy (melting of olivine results in a degradation of the Raman spectra due to loss of olivine crystal structure). This observation is backed up by hydrocode modelling which demonstrates that the temperatures at maximum pressures (Table 1) experienced by the olivine and basaltic impactors do not reach their melting point, which is 2100 K and 2500 K at pressures of 10 GPa and 4.6 GPa respectively.…”

Section: Discussionmentioning

confidence: 65%

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

Avdellidou¹,

Price²,

Delbò³

et al. 2015

Mon. Not. R. Astron. Soc.

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Recent observations of asteroidal surfaces indicate the presence of materials that do not match the bulk lithology of the body. A possible explanation for the presence of these exogenous materials is that they are products of inter-asteroid impacts in the Main Belt, and thus interest has increased in understanding the fate of the projectile during hypervelocity impacts. In order to gain insight into the fate of impactor we have carried out a laboratory programme, covering the velocity range of 0.38 -3.50 km/s, devoted to measuring the survivability, fragmentation and final state of the impactor. Forsterite olivine and synthetic basalt projectiles were fired onto low porosity (<10%) pure water-ice targets using the University of Kent's Light Gas Gun (LGG). We developed a novel method to identify impactor fragments which were found in ejecta and implanted into the target. We applied astronomical photometry techniques, using the SOURCE EXTRACTOR software, to automatically measure the dimensions of thousands of fragments. This procedure enabled us to estimate the implanted mass on the target body, which was found to be a few percent of the initial mass of the impactor. We calculated an order of magnitude difference in the energy density of catastrophic disruption, Q*, between peridot and basalt projectiles. However, we found very similar behaviour of the size frequency distributions for the hypervelocity shots (>1 km/s). After each shot, we examined the largest peridot fragments with Raman spectroscopy and no melt or alteration in the final state of the projectile was observed.

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“…The latter process occurs when smaller asteroids impact larger ones 6 . These impacts can be highly erosive due to characteristic speeds ∼5 km s −1 (Bottke et al 1994) and the amount of ejected mass can be significant. However, typical impact events in the main-belt have an impact probability ∼3.0 × 10 −8 km −2 yr −1 (Farinella & Davis 1992).…”

Section: Water Mass Loss Processmentioning

confidence: 99%

Asteroid flux towards circumprimary habitable zones in binary star systems

Bancelin

Pilat-Lohinger

Eggl

et al. 2015

A&A

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Context. So far, more than 130 extrasolar planets have been found in multiple stellar systems. Dynamical simulations show that the outcome of the planetary formation process can lead to different planetary architecture (i.e. location, size, mass, and water content) when the star system is single or double. Aims. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (HZ). In this study, we make a comparison of several binary star systems and how efficient they are at moving icy asteroids from beyond the snow line into orbits crossing the HZ. Methods. We modelled a belt of 10 000 asteroids (remnants from the late phase of the planetary formation process) beyond the snow line. The planetesimals are placed randomly around the primary star and move under the gravitational influence of the two stars and a gas giant. As the planetesimals do not interact with each other, we divided the belt into 100 subrings which were integrated separately. In this statistical study, several double star configurations with a G-type star as primary are investigated. Results. Our results show that small bodies also participate in bearing a non-negligible amount of water to the HZ. The proximity of a companion moving on an eccentric orbit increases the flux of asteroids to the HZ, which could result in a more efficient water transport on a short timescale, causing a heavy bombardment. In contrast to asteroids moving under the gravitational perturbations of one G-type star and a gas giant, we show that the presence of a companion star not only favours a faster depletion of our disk of planetesimals, but can also bring 4-5 times more water into the whole HZ.

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Velocity Distributions among Colliding Asteroids

Cited by 387 publications

References 0 publications

Chaotic diffusion caused by close encounters with several massive asteroids

Chaotic diffusion caused by close encounters with several massive asteroids

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

Asteroid flux towards circumprimary habitable zones in binary star systems

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