Space Weathering of Small Solar System Bodies

Brunetto, R.

doi:10.1007/s11038-009-9340-9

Cited by 15 publications

(7 citation statements)

References 45 publications

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“…Lunar-style space weathering increases spectral slope and decreases band depth and albedo (Hapke 2001;Noble et al 2001;Pieters et al 2000;Taylor et al 2001). While many laboratory experiments on ordinary chondrites or their mineral constituents reveal space weathering effects similar to lunarstyle such as increased spectral slope reddening and decreased albedos (Sasaki et al 2001;Clark et al 2002;Chapman 2004;Brunetto and Strazzulla 2005;Brunetto et al 2006a,b;Brunetto 2009), space weathering on S-complex asteroids as seen by spacecraft missions do not follow lunar-style trends nor do they display weathering trends consistent with each other (e.g., Veverka et al 1996;Helfenstein et al 1996;Clark et al 2001;Murchie et al 2002;Bell et al 2002a;Gaffey 2010). This might not be surprising, however, given that the S-complex encompasses a diverse set of compositions (e.g., Gaffey et al 1993;Dunn et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Mars encounters cause fresh surfaces on some near-Earth asteroids

DeMeo

Binzel

Lockhart

2014

Icarus

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All airless bodies are subject to the space environment, and spectral differences between asteroids and meteorites suggest many asteroids become weathered on very short (<1My) timescales. The spectra of some asteroids, particularly Q-types, indicate surfaces that appear young and fresh, implying they have been recently been exposed. Previous work found that Earth encounters were the dominant freshening mechanism and could be responsible for all near-Earth object (NEO) Q-types. In this work we increase the known NEO Q-type sample of by a factor of three. We present the orbital distributions of 64 Q-type near-Earth asteroids, and seek to determine the dominant mechanisms for refreshing their surfaces. Our sample reveals two important results: i) the relatively steady fraction of Q-types with increasing semi-major axis and ii) the existence of Q-type near-Earth asteroids with Minimum Orbit Intersection Distances (MOID) that do not have orbit solutions that cross Earth. Both of these are evidence that Earth-crossing is not the only scenario by which NEO Q-types are freshened. The high Earth-MOID asteroids represent 10% of the Q-type population and all are in Amor orbits. While surface refreshing could also be caused by Main Belt collisions or mass shedding from YORP spinup, all high Earth-MOID Q-types have the possibility of encounters with Mars indicating Mars could be responsible for a significant fraction of NEOs with fresh surfaces.

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Section: Introductionmentioning

confidence: 99%

Mars encounters cause fresh surfaces on some near-Earth asteroids

DeMeo

Binzel

Lockhart

2014

Icarus

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“…For most classes of asteroids and meteorites, space weathering remains poorly understood, also because of the scarcity of dedicated experiments (Lazzarin et al 2006;Brunetto 2009;Gaffey 2010). Among these different taxonomic classes, the V-type asteroids (Binzel & Xu 1993;DeMeo et al 2009) are an interesting test case for space weathering studies.…”

Section: Introductionmentioning

confidence: 99%

Space weathering of Vesta and V-type asteroids: new irradiation experiments on HED meteorites

Fulvio

Brunetto

Vernazza

et al. 2012

A&A

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Context. In the past few decades, several tens of main belt asteroids have been found to exhibit basaltic surface composition, similar to the one of Vesta and basaltic Howardite, Eucrite, and Diogenite achondrite meteorites (HEDs). Most of these objects (V-types) belong to the Vesta dynamical family. Several questions on the relationship between Vesta, V-types, and HEDs are still unresolved. In particular, Vesta is spectroscopically bluer than most V-types. Aims. To date, it has not yet been understood whether these spectral differences are due to space weathering, similar to what has been observed for OC meteorites and S-type asteroids. To test this hypothesis, ion irradiation experiments were performed on different samples of eucrites to simulate the effects of space weathering on Vesta and V-types by solar wind ions. Methods. Eucrite meteorites were analyzed before and after different stages of ion irradiation by VIS-NIR reflectance spectroscopy (0.4-2.5 μm). We used different ions (Ar + , C + ) with different energies (from 60 to 200 keV) to weather the samples. Results. Ion irradiation was observed to alter the spectral properties of eucrite meteorites, inducing progressive reddening and darkening of the irradiated samples. Different eucrite samples (Bereba and Dar Al Gani 684) show different reddening behaviors. Because they are patchy, reddening also varied between different parts of the same meteorite. Moreover, for both meteorites, irradiation effects are much faster (∼100 times) for C + than for Ar + ions. Conclusions. Comparing the laboratory spectra of eucrites before and after different stages of ion irradiation with those of V-types, it turns out that the slope spread shown by V-type asteroids can be explained by space weathering. These results provide new clues to the connection between Vesta, V-types, and HEDs, and are also useful in the context of the NASA Dawn mission to Vesta.

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“…Next, the Lorre cluster may be very useful to improve our knowledge about space weathering processes acting on primitive bodies, a debated subject since results based on the Sloan Digital Sky Survey broadband photometry (Nesvorný et al 2005) are not consistent with the results of some laboratory experiments (Brunetto 2009).…”

Section: Discussionmentioning

confidence: 99%

Recent collisional jet from a primitive asteroid

Novaković

Dell’Oro

Cellino

et al. 2012

Monthly Notices of the Royal Astronomical Society

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Here we show an example of a young asteroid cluster located in a dynamically stable region, which was produced by partial disruption of a primitive body about 30 km in size. We estimate its age to be only 1.9 +/- 0.3 Myr, thus its post-impact evolution should have been very limited. The large difference in size between the largest object and the other cluster members means that this was a cratering event. The parent body had a large orbital inclination, and was subject to collisions with typical impact speeds higher by a factor of 2 than in the most common situations encountered in the main belt. For the first time we have at disposal the observable outcome of a very recent event to study high-speed collisions involving primitive asteroids, providing very useful constraints to numerical simulations of these events and to laboratory experiments.Comment: Accepted for publication by MNRA

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Space Weathering of Small Solar System Bodies

Cited by 15 publications

References 45 publications

Mars encounters cause fresh surfaces on some near-Earth asteroids

Mars encounters cause fresh surfaces on some near-Earth asteroids

Space weathering of Vesta and V-type asteroids: new irradiation experiments on HED meteorites

Recent collisional jet from a primitive asteroid

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