Lingering grains of truth around comet 17P/Holmes

TL;DR

This study analyzes comet 17P/Holmes three years after its 2007 outburst using infrared imaging, revealing details about its nucleus, coma, and dust trail, and providing insights into its physical properties and dust ejection history.

Contribution

It provides the first detailed characterization of the comet's nucleus and dust trail post-outburst using infrared data and modeling, enhancing understanding of cometary activity and dust ejection.

Findings

Nucleus diameter approximately 4.1 km.

Dust trail composed of grains 250 μm to a few cm.

Trail mass estimated between 1.2 and 5.3 x 10^10 kg.

Abstract

Comet 17P/Holmes underwent a massive outburst in 2007 Oct., brightening by a factor of almost a million in under 48 hours. We used infrared images taken by the Wide-Field Survey Explorer mission to characterize the comet as it appeared at a heliocentric distance of 5.1 AU almost 3 years after the outburst. The comet appeared to be active with a coma and dust trail along the orbital plane. We constrained the diameter, albedo, and beaming parameter of the nucleus to 4.135 $\pm$ 0.610 km, 0.03 $\pm$ 0.01 and 1.03 $\pm$ 0.21, respectively. The properties of the nucleus are consistent with those of other Jupiter Family comets. The best-fit temperature of the coma was 134 $\pm$ 11 K, slightly higher than the blackbody temperature at that heliocentric distance. Using Finson-Probstein modeling we found that the morphology of the trail was consistent with ejection during the 2007 outburst and was made up of dust grains between 250 $\mu$m and a few cm in radius. The trail mass was $\sim$ 1.2 - 5.3 $\times$ 10$^{10}$ kg.