![Simulated ablation heights of IDPs in exoplanet atmospheres. Our fiducial simulation is marked in red. Solid and dashed curves signify IDP compositions of MgSiO3 and Fe, respectively. The black dashed curve on the left most panel shows the approximation of the mass injection function Fv(p) for an arbitrary IDP mass flux for comparison with the ablation profiles. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Interplanetary-Dust.png?fit=1200%2C679&ssl=1)
[astro-ph.EP] Interplanetary dust particles (IDPs) are present throughout the Solar System, with Earth experiencing a mass flux of roughly 100 tonnes of IDPs per day.
These particles ablate in the upper atmosphere, delivering aerosols that form noctilucent and stratospheric clouds. Since IDPs are present in exoplanet systems as exozodiacal dust disks (exozodis), it is likely that exoplanets experience a constant infall of IDPs as well.
Connection between Interplanetary Dust Particles (IDPs) and cloud formation in planetary atmospheres. The ablation products of IDPs nucleate and condense at high altitudes, providing Cloud Condensation Nuclei (CCNs) for cloud materials diffusing from the planetary interior. The additional source of CCNs affects cloud particle radii, number densities, and Mass Mixing Ratios (MMRs). The differently coloured particles represent cloud particle materials. — [astro-ph.EP]
In this work, we investigate the effect of IDPs on the cloud structure of gas-giant exoplanets and brown dwarfs, and determine their observability.
We apply the microphysical cloud model Nimbus to the Sonora Diamondback model grid to cover a wide range of effective temperatures, surface gravities, atmospheric mixing constants, and IDP mass fluxes.
Our results show that IDP infall increases cloud particle number densities, decreases cloud particle radii, and enhances silicate features in transmission and thermal emission spectra. Exoplanets with lower atmospheric mixing rates, effective temperatures, and gravity are more sensitive to IDPs.
Most notably, they lead to observable silicate absorption features in colder planets where silicate clouds would otherwise not be observable. WASP-107 b is an example of such an exoplanet with observational evidence of silicate particles.
Using Nimbus, we found that a 100 times Earth-like IDP mass flux with a Solar-System-like IDP composition of quartz (SiO2), enstatite (MgSiO3), and iron (Fe) can explain the observations of high altitude silicate particles in WASP-107 b.
Sven Kiefer, Gregory J. Gosselin, Caroline V. Morley, Sean P. S. Gulick
Comments: 18 pages, 8 Figures, accepted for publication in ApJ Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2609.08960 [astro-ph.EP](or arXiv:2609.08960v1 [astro-ph.EP] for this version) https://doi.org/10.48550/arXiv.2609.08960
Focus to learn more Submission history
From: Sven Kiefer [v1]
Tue, 8 Sep 2026 16:14:59 UTC (1,690 KB)
https://arxiv.org/abs/2609.08960
Astrobiology,
