Exozodiacal dust

Source: Wikipedia, the free encyclopedia.
This artist's view from an imagined planet around a nearby star shows the brilliant glow of exozodiacal light extending up into the sky and swamping the Milky Way.

Exozodiacal dust is 1–100 micrometre-sized grains of

extrasolar planets, and potentially indicate the presence of these planets. Because it is often located near a star's habitable zone
, exozodiacal dust can be an important noise source for attempts to image terrestrial planets. Around 1 in 100 stars in the nearby solar systems shows a high content of warm dust that is around 1000 times greater than the average dust emission in the 8.5–12 μm range.

Formation

Although such dust was initially theoretical, we have now observed its infrared signature while attempting to observe exo-earths.

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.[3] Leftover particulates from the formation of a solar system, as well as debris from the collisions of larger objects leave behind exozodiacal dust.[4] 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 solar systems throughout the Milky Way.[5] Dust from different sources, such as from asteroid collisions, comets, and trapped particulates, are theorized to form different infrared structures, respectively.[6]

Examples of stars with exozodiacal dust

Ongoing research

Observations have found that some spectral type A-K have the infrared signatures of exozodiacal dust much closer to the star than is theorized to be possible. Within a certain circumference of the star, the dust is expected to be ground down and ejected by the star within a few years. While the dust has been confirmed to exist this close to a star, models still cannot explain its presence.[1] Modeling the behavior of both zodiacal and exozodiacal dust is a noteworthy area of research, as the dust presents itself as noise for astronomers attempting to observe planetary bodies. If the dust can be accurately modeled, it can be subtracted out of observations of exo-earths.[2]

References

  1. ^
    Bibcode:2016AAS...22722807S
    .
  2. ^
    S2CID 53323345
    .
  3. ^ "Dust Grain | COSMOS". astronomy.swin.edu.au. Retrieved 2017-10-16.
  4. ^ "Comet or Asteroid? Big Space Rock Has Identity Crisis". Space.com. Retrieved 2017-10-16.
  5. ^ "Cool Cosmos". coolcosmos.ipac.caltech.edu. Archived from the original on 2020-02-23. Retrieved 2017-10-16.
  6. ^ "An Improved Model for That Pesky Zodiacal Dust". Astrobites. 2013-01-04. Retrieved 2017-10-16.
  7. S2CID 12112032
    .
  8. ^
    S2CID 13144157
    .
  9. S2CID 9594917
    . A128.

External links
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