Exocomet

They are considered fossil bodies that have seen the physical and chemical conditions prevailing at the time of planet formation.

[citation needed] Researching exocomets might provide answers to fundamental questions of the past of the solar system and the development of a life-supporting environment.

Researchers can investigate the transport of water, cyanides, sulfides and pre-biotic molecules onto Earth-mass exoplanets with the help of exocomets.

Changes are observed in the absorption lines of the stellar spectrum: the occultation of the star by the gas cloud coming from the exocomet produces additional absorption features beyond those normally seen in that star, like those observed in the ionized calcium lines.

As the comet comes close enough to the star, cometary gas is evolved from the evaporation of volatile ices and dust with it.

The Kepler mission detected asymmetrical dips around KIC 3542116, a F2V-type star that are consistent with models of transiting exocomets.

The dips were found by one of the authors, a Planet Hunters participant, in a visual search over 5 months of the complete Q1-Q17 Kepler light curve archive spanning 201250 target stars.

[24] During formation of the Oort Cloud through planetary perturbations, stellar encounters, and the galactic tide, a comet can be ejected and leave the solar system.

[28] These ejected exocomets belong to the interstellar comets and can be observed directly if they enter the solar system.

[34] In 2017 a study concluded that spectral lines in the white dwarf WD 1425+540 are attributed to an accretion of a Kuiper-Belt analog.