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Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
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Predicting observable infrared signatures of nanosilicates in the diffuse interstellar medium
Sascha T Zeegers1, Joan Mariñoso Guiu2, Francisca Kemper3,4,5
1European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands.
Faraday Discussions
|June 19, 2023
Summary
Interstellar dust grains must reform in space as they are destroyed quickly. This study uses quantum calculations to predict the spectral signature of nanograins, potentially confirming interstellar dust formation with the James Webb Space Telescope.
Area of Science:
- Astrophysics
- Cosmic Dust Studies
- Astrochemistry
Background:
- Interstellar dust destruction timescales are shorter than their residence times, implying dust reformation and grain growth.
- Direct observation of nanometer-sized silicate grains would confirm condensation in the diffuse interstellar medium.
Purpose of the Study:
- To calculate mid-infrared optical properties of silicate nanoparticles.
- To predict the spectral signature of nanosilicate grains in the interstellar medium.
- To assess the detectability of nanosilicate fractions with the James Webb Space Telescope (JWST).
Main Methods:
- Quantum chemical calculations for silicate nanoparticle optical properties.
- Foreground-screen modeling using calculated optical properties.
- Spectral analysis of silicate mixtures towards background stars.
Main Results:
- Mid-infrared spectra change when ~3% of silicate mass is in the form of nanosilicates.
- A 3-10% nanosilicate fraction is predicted to be detectable with JWST's Mid-Infrared Instrument (MIRI).
Conclusions:
- JWST/MIRI observations can detect or constrain nanosilicate content in the diffuse interstellar medium.
- This research offers a pathway to directly confirm interstellar dust formation.
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