Comets around other stars than the Sun – exocomets – have so far only been possible to discover indirectly, when they pass in front of their parent stars as seen from Earth. In a new study accepted for publication in Astronomy & Astrophysics, Janson et al. (arxiv) show that LIFE can be used to detect exocomets directly, and to study their properties. In the systems with the most extreme comet activity, such as beta Pictoris, exocomets detectable with LIFE may even be so common that they overcrowd the field of view. When exocomets are discovered directly, it becomes possible to study their spectra and thereby examine what the comets are made of, which in turn can give clues about where in the system they originated from. Comets are believed to be of great importance in the context of habitability and life in the universe, since on one hand, they transfer water from the ice-rich outer parts of planetary systems into the otherwise dry inner parts of the systems where Earth-like planets reside, and on the other hand, they can cause extinctions through catastrophic collisions with planets. Being able to study comets directly in other systems therefore provides a new additional tool to better understand the conditions for habitability on other worlds.

Figure caption: Simulation of a young comet-rich extrasolar system. Left: Each circle is a simulated exocomet, where the size of the circle denotes the size of the comet (not to scale with the distances in the figure). The dashed lines are the orbits of the comets. Right: An example of what the simulated system looks like when observed with the nulling interferometry technique that LIFE will use.