Candidates for Asteroid Dust Trails

Abstract

The contribution of different sources to the circumsolar dust cloud (known as the zodiacal cloud) can be deduced from diagnostic observations. We used the Spitzer Space Telescope to observe the diffuse thermal emission of the zodiacal cloud near the ecliptic. Several structures were identified in these observations, including previously known asteroid dust bands, which are thought to have been produced by recent asteroid collisions, and cometary trails. Interestingly, two of the detected dust trails, denoted t1 and t2 here, cannot be linked to any known comet. Trails t1 and t2 represent a much larger integrated brightness than all known cometary trails combined and may therefore be major contributors to the circumsolar dust cloud. We used our Spitzer observations to determine the orbits of these trails and were able to link them to two (''orphan'' or type II) trails that were discovered by the Infrared Astronomical Satellite (IRAS ) in 1983. The orbits of trails t1 and t2 that we determined by combining the Spitzer and IRAS data have semimajor axes, eccentricities, and inclinations like those of the main-belt asteroids. We therefore propose that trails t1 and t2 were produced by very recent (P100 kyr old) collisional breakups of small, P10 km diameter main-belt asteroids.

New Candidates for Recent Asteroid Breakups

“…It is therefore possible that the clusters discussed here are sources of some of the material in the circumsolar (zodiacal ) dust cloud. Depending on the exact value of t age and location in the main belt, they may be related to some dust trails (see, e.g., Sykes 1986;Sykes & Walker 1992;Nesvorný et al 2006c) or to dust bands (see, e.g., Dermott et al 1984;Sykes & Greenberg 1986;Nesvorný et al 2006b). For example, Sykes (1986Sykes ( , 1988 has identified a number of faint dust bands in observations by the Infrared Astronomical Satellite that have never been successfully linked to their sources in the main belt (except those discussed in Nesvorný et al 2003).…”

Irregular Satellites of the Planets: Products of Capture in the Early Solar System

“…The mass of Himalia has been estimated, from its perturbations on other satellites (principally J VII Elara), as 4.2 ± 0.6×10 18 kg (Emelyanov 2005). The prograde family of which Himalia is the dominant member has a velocity dispersion significantly larger than expected on the basis of numerical models of satellite disruption by collision (Nesvorný et al 2003). Christou (2005) explores the possibility that this could be an artifact of gravitational scattering of the fragments after disruption using models for Himalia mass estimates in the range 1.7×10 18 kg to 5.2×10 18 kg.…”

“…Neither is it an expected consequence of long-term dynamical instability. Nesvorný et al (2003) noted that the satellites of the outer planets would be destroyed by mutual collisions in the lifetime of the Solar system if displaced to orbits around Jupiter. On this basis, they assert that the a/r H versus a p trend could be a result of past collisional depletion.…”

Dirbe Comet Trails

“…Therefore it had been recognized that the interplanetary dust needs to be continually replenished from new sources of dust. IRAS provided clear evidence for replenishment by main belt asteroids with the discovery of "bands" at low ecliptic latitudes (Low et al 1984;Sykes 1988;Nesvorný et al 2006). IRAS also provided evidence of replenishment by comets with "the discovery of dust trails in the orbits of periodic comets" (Sykes et al 1986).…”