THE ACTIVE ASTEROIDS

By D. Jewitt. 2011

348 citations recorded by the source corpus.

Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass-losing asteroids (also called “main-belt comets”) can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider 11 dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses, and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation, while in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2, but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is probably due to cracking or dehydration at extreme (∼1000 K) perihelion temperatures, perhaps aided by radiation pressure sweeping. For the other bodies, the mass-loss mechanisms remain unidentified, pending the acquisition of more and better data. While the active asteroid sample size remains small, the evidence for an astonishing diversity of mass-loss processes in these bodies is clear.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/560e0fbf059b780a3583341abd962598e81adde0

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In Astronomy and Astrophysics

Citations in the corpus

The Zwicky Transient Facility: Science Objectives (2019, background): “…events such as cometary outbursts and fragmentation events (Ye et al. 2015; Ishiguro et al. 2016), collisions between asteroids (Snodgrass et al. 2010; Bodewits et al. 2011), unexpected or irregular activity in asteroids (Jewitt 2012; Waszczak et al. 2013; Ye 2017) and Centaurs (Jewitt 2009).”
LSST: From Science Drivers to Reference Design and Anticipated Data Products (2008, background): “Only a few such objects are currently known (Jewitt et al. 2011; Jewitt 2012); LSST will increase the sample of such objects to ∼100.”
Water delivery and giant impacts in the 'Grand Tack' scenario (2014, positive): “This value is probably conservative given that asteroids known as main-belt comets appear to have a much larger water content than this (Jewitt, 2012).”