Local manifestations of cometary activity

Abstract

Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity. Although the basic principles are well established, most details remain elusive, especially regarding the mechanisms by which dust is detached from the surface and subsequently accelerated by the gas flows surrounding the nucleus. During its 2 years rendez-vous with comet 67P/Churyumov-Gerasimenko, ESA's Rosetta has observed cometary activity with unprecedented details, in both the inbound and outbound legs of the comet's orbit. This trove of data provides a solid ground on which new models of activity can be built. In this chapter, we review how activity manifests at close distance from the surface, establish a nomenclature for the different types of observed features, discuss how activity is at the same time transforming and being shaped by the topography, and finally address several potential mechanisms.

This paper is a review chapter in the upcoming book "Comets: Post 67P Perspectives" edited by ISSI and Space Science Reviews. Accepted on 08 April 2019

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Cited by in corpus (3)

• The thermal, mechanical, structural, and dielectric properties of cometary nuclei after Rosetta
• The ice composition close to the surface of comet 67P/Churyumov-Gerasimenko
• Searching for Outbursts in the Ground-Based Photometry of 67P/Churyumov-Gerasimenko