Circumstellar dust

Circumstellar dust is cosmic dust around a star. It can be in the form of a spherical shell or a disc, e.g. an accretion disk. Circumstellar dust can be responsible for significant extinction and is usually the source of an infrared excess for stars that have it. For some evolved stars on the asymptotic giant branch, the dust can be composed of silicate emissions.[1] According to a study, it is still uncertain whether the dust is a result of crystalline silicate or polycyclic aromatic hydrocarbon.[2] However, recent observations revealed that Vega-type stars display broad silicate emission.[2] It is suggested that the circumstellar dust components can depend on the evolutionary stage of a star and is related to the changes in its physical conditions.[3]

The study of the composition of this dust is dubbed astrominerology. The circumstellar dust around aging stars has been observed to include, "almost pure crystalline Mg-rich silicates (forsterite and clinoenstatite), amorphous silicates, diopside, spinel, oxides (corundum and Fe0.9Mg0.1O), and also carbon-rich solids such as: (hydrogenated) amorphous carbons, aromatic hydrocarbons and silicon carbide."[4]

The motion of circumstellar dust is governed by forces due to stellar gravity and radiation pressure.

Circumstellar dust in the Solar System causes the zodiacal light.

  1. ^ Nakada, Y.; Honma, M.; Seki, M. (2003). Mass-Losing Pulsating Stars and their Circumstellar Matter: Observations and Theory. Dordrecht: Kluwer Academic Publishers. p. 258. ISBN 1402011628.
  2. ^ a b Käufl, Hans U.; Siebenmorgen, Ralf (2013). The Role of Dust in the Formation of Stars: Proceedings of the ESO Workshop Held at Garching, Germany, 11–14 September 1995. Berlin: Springer Science & Business Media. p. 170. ISBN 9783662225158.
  3. ^ Hony, Sacha (2003). Infrared Light on the Composition of the Dust Surrounding Carbon-Rich Stars. Amsterdam: Amsterdam University Press. p. 7. ISBN 9053566686.
  4. ^ Jones, Anthony P. (2019). "The mineralogy of cosmic dust: astromineralogy". European Journal of Mineralogy. 19 (6): 771–782. doi:10.1127/0935-1221/2007/0019-1766.