Exozodiacal dust

Formation

Although such dust was initially theoretical, we have now observed its infrared signature while attempting to observe exo-earths. As exozodiacal dust is the extrasolar equivalent of zodiacal dust, its formation is theorized to be the same. This is to be contrasted with interstellar dust, which is not trapped in a solar system. Leftover particulates from the formation of a planetary system, as well as debris from the collisions of larger objects leave behind exozodiacal dust. The amount of potential exozodiacal dust is thought to be ever-decreasing, though, as massive bodies like planets absorb significant amounts of it. For instance, the Earth absorbs 40,000 tons of this dust every year. The dust emits infrared radiation, and through gravitational interactions with bodies such as the Sun it forms infrared rings. These rings have been observed across many planetary systems throughout the Milky Way. Dust from different sources, such as from asteroid collisions, comets, and trapped particulates, are theorized to form different infrared structures, respectively.