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Astro Seminar

Destruction and re-formation of grains in an inhomogeneous, multiphase interstellar matter

Speaker: Dr Svitlana Zhukovska (Exeter)
Date: Wednesday 16 October 2019
Time: 14:00
Venue: Queens Buildings N/3.28

Dust is small, but important component of the interstellar medium (ISM) of any galaxy. The fraction of metals in dust is not the same: it varies among galaxies and even in the local Milky Way. These variations hold the key to understanding the long-standing questions on where interstellar grains come from and how they evolve in the ISM. We study these questions with models of dust evolution using both simple galactic chemical evolution models and high-resolution hydrodynamic simulations. Simple models allow identifying the roles of stellar and non-stellar dust sources in local galaxies, while simulations are used to shed light on the physics of dust processing in ISM. For the Milky Way, we find that the observed distribution of interstellar dust abundances supports the evolutionary scenario in which grains cycle between ISM phases on short timescales alternating between efficient sputtering in supernova blast waves and subsequent re-formation by accretion of gas species in the cold, neutral medium. I will discuss what recent simulations tell us about physical conditions and timescales of dust destruction and growth in the ISM.