A survey of debris trails from short-period comets

TL;DR

This survey used the Spitzer Space Telescope to observe 34 short-period comets, revealing debris trails in over 80% of cases, primarily composed of millimeter-sized particles, indicating debris trails are common features of such comets.

Contribution

It provides the first comprehensive survey of debris trails in short-period comets, establishing their high occurrence rate and characterizing particle sizes and mass loss.

Findings

Debris trails detected in over 80% of observed comets.

Most debris particles are millimeter-sized.

Median mass loss rate from debris trails is 2 kg/s.

Abstract

We observed 34 comets using the 24 micron camera on the Spitzer Space Telescope. Each image contains the nucleus and covers at least 10^6 km of each comet's orbit. Debris trails due to mm-sized or larger particles were found along the orbits of 27 comets; 4 comets had small-particle dust tails and a viewing geometry that made debris trails impossible to distinguish; and only 3 had no debris trail despite favorable observing conditions. There are now 30 Jupiter-family comets with known debris trails, of which 22 are reported in this paper for the first time. The detection rate is >80%, indicating that debris trails are a generic feature of short-period comets. By comparison to orbital calculations for particles of a range of sizes ejected over 2 yr prior to observation, we find that particles comprising 4 debris trails are typically mm-sized while the remainder of the debris trails require particles larger than this. The lower-limit masses of the debris trails are typically 10^11 g, and the median mass loss rate is 2 kg/s. The mass-loss rate in trail particles is comparable to that inferred from OH production rates and larger than that inferred from visible-light scattering in comae.