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{{Short description|Dust around a star}}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.BOOK, Mass-Losing Pulsating Stars and their Circumstellar Matter: Observations and Theory, Nakada, Y., Honma, M., Seki, M., Kluwer Academic Publishers, 2003, 1402011628, Dordrecht, 258, According to a study, it is still uncertain whether the dust is a result of crystalline silicate or polycyclic aromatic hydrocarbon.BOOK, The Role of Dust in the Formation of Stars: Proceedings of the ESO Workshop Held at Garching, Germany, 11–14 September 1995, Käufl, Hans U., Siebenmorgen, Ralf, Springer Science & Business Media, 2013, 9783662225158, Berlin, 170, However, recent observations revealed that Vega-type stars display broad silicate emission. 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.BOOK, Infrared Light on the Composition of the Dust Surrounding Carbon-Rich Stars, Hony, Sacha, Amsterdam University Press, 2003, 9053566686, Amsterdam, 7, 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."JOURNAL , 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.

See also

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• Accretion disc
• Circumplanetary disk
• Circumstellar envelope
• Tabby's Star − oddly dimming star
• List of stars that have unusual dimming periods
• WD 1145+017 - star destroying planetesimal, producing a dusty disk

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Sources

• BOOK, J. Mayo Greenberg, H. C. Van De Hulst, Interstellar Dust and Related Topics, 17 April 2013, Springer Science & Business Media, 2013, 978-9401026642,
• BOOK, Hans-Peter Gail, Erwin Sedlmayr, Physics and Chemistry of Circumstellar Dust Shells, 2014, Cambridge University Press, 2013, 978-0521833790,
• BOOK, K. S. Krishna Swamy, Dust in the Universe: Similarities and Differences, World Scientific, 2005, 9812562931, Chapter 6: Circumstellar dust, 2005,
• BOOK, Marshall Dimsey Perrin, A High Angular Resolution Survey of Circumstellar Dust Around Herbig Ae/Be Stars, University of California, Berkeley, 2006, 1109923074,
• BOOK, Wilfred Henry Sorrell, A Theoretical Study of Circumstellar Dust Around Ae/Be Stars, University of Wisconsin--Madison, 1989,

References

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