Comets have three known reservoirs: the roughly spherical Oort Cloud (for long-period
comets), the flattened Kuiper Belt (for ecliptic comets), and, surprisingly, the asteroid belt (for …

This review addresses our current understanding of comets that venture close to the Sun,
and are hence exposed to much more extreme conditions than comets that are typically …

This paper uses observations of dusty debris discs, including a growing number of gas
detections in these systems, to test our understanding of the origin and evolution of this …

The presence of CO gas around 10–50 Myr old A stars with debris discs has sparked debate
on whether the gas is primordial or secondary. Since secondary gas released from …

Exocomets are small bodies releasing gas and dust which orbit stars other than the Sun.
Their existence was first inferred from the detection of variable absorption features in stellar …

Context. While exoplanets are now routinely detected, the detection of small bodies in
extrasolar systems remains challenging. Since the discovery of sporadic events, which are …

The TRAPPIST-1 system is unique in that it has a chain of seven terrestrial Earth-like planets
located close to or in its habitable zone. In this paper, we study the effect of potential …

We investigate the plausibility of a cometary source of the unusual transits observed in the
KIC 8462852 light curve. A single comet of similar size to those in our solar system produces …

Debris disks are considered to be gas-poor, but recent observations revealed molecular or
atomic gas in several 10–40 Myr old systems. We used the APEX and IRAM 30 m radio …

Active comets have been detected in several exoplanetary systems, although so far only
indirectly, when the dust or gas in the extended coma has transited in front of the stellar disk …