Distribution of boulders and the gravity potential on asteroid Itokawa

Tancredi, G.; Roland, S.; Bruzzone, Juan Sebastián

doi:10.1016/j.icarus.2014.10.011

Cited by 47 publications

(41 citation statements)

References 21 publications

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“…This probably reflects the asteroid regolith size distribution. Broken power-law functions are common when describing the size distributions of asteroid dust bands (Nesvorný et al 2006), the boulder distribution in asteroid regoliths (Tancredi et al 2015), or in cometary dust (Fulle et al 2016, Moreno et al 2016, always with a tendency to increase slope with size.…”

Section: Resultsmentioning

confidence: 99%

Dust properties of double-tailed active asteroid (6478) Gault

Moreno

Jehin

Licandro

et al. 2019

A&A

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Context. Asteroid (6478) Gault was discovered to exhibit a comet-like tail in observations from December 2018, becoming a new member of the so-called active asteroid population in the main asteroid belt. Aims. The aims are to investigate the grain properties of the dust ejected from asteroid (6478) Gault and to give insight into the activity mechanism(s). Methods. We use a Monte Carlo dust tail brightness code to retrieve the dates of dust ejection, the physical properties of the grains, and the total dust mass losses during each event. The code takes into account the brightness contribution of the asteroid itself. The model is applied to a large data set of images spanning the period from January 11, 2019 to March 13, 2019. In addition, both shortand long-term photometric measurements of the asteroid have been carried out. Results. It is shown that, to date, asteroid (6478) Gault has experienced two episodes of impulsive dust ejection, that took place around 2018 November 5 and 2019 January 2, releasing at least 1.4×10 7 kg and 1.6 ×10 6 kg of dust, respectively, at escape speeds. The size distribution, consisting of particles in the 1 µm to 1 cm radius range, follows a broken power-law with bending points near 15 µm and 870 µm. On the other hand, the photometric series indicate a nearly constant magnitude over several 5-7.3 h periods, a possible effect of the masking of a rotational lightcurve by the dust. Conclusions. The dust particles forming Gault's tails were released from the asteroid at escape speeds, but the specific ejection mechanism is unclear until photometry of the dust-free asteroid are conducted, in order to assess whether this was related to rotational disruption or to other possible causes.

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Section: Resultsmentioning

confidence: 99%

Dust properties of double-tailed active asteroid (6478) Gault

Moreno

Jehin

Licandro

et al. 2019

A&A

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“…Finally, irrespective of the variety of BNE, it is perplexing that boulders do roll 5 , but do not make their way into gravitational valleys 26 , and instead perch on highlands 2 leaving valleys populated almost entirely by pebbles 4 . We propose here an alternative, and much simpler, mechanism of size segregation on rubble pile asteroids such as Itokawa.…”

Section: Doi: …mentioning

confidence: 99%

Size Sorting on the Rubble-Pile Asteroid Itokawa

et al. 2017

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“…4. Spacecraft images have shown that some asteroids have large boulders that seem to be protruding from their surfaces such as Eros (Asphaug et al, 2001) and Itokawa (Miyamoto et al, 2007;Tancredi et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

The spherical Brazil Nut Effect and its significance to asteroids

Perera

Jackson

Asphaug

et al. 2016

Icarus

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Many asteroids are likely rubble-piles that are a collection of smaller objects held together by gravity and possibly cohesion. These asteroids are seismically shaken by impacts, which leads to excitation of their constituent particles. As a result it has been suggested that their surfaces and sub-surface interiors may be governed by a size sorting mechanism known as the Brazil Nut Effect. We study the behavior of a model asteroid that is a spherical, self-gravitating aggregate with a binary size-distribution of particles under the action of applied seismic shaking. We find that above a seismic threshold, larger particles rise to the surface when friction is present, in agreement with previous studies that focussed on cylindrical and rectangular box configurations. Unlike previous works we also find that size sorting takes place even with zero friction, though the presence of friction does aid the sorting process above the seismic threshold. Additionally we find that while strong size sorting can take place near the surface, the innermost regions remain unsorted under even the most vigorous shaking.

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Distribution of boulders and the gravity potential on asteroid Itokawa

Cited by 47 publications

References 21 publications

Dust properties of double-tailed active asteroid (6478) Gault

Dust properties of double-tailed active asteroid (6478) Gault

Size Sorting on the Rubble-Pile Asteroid Itokawa

The spherical Brazil Nut Effect and its significance to asteroids

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