Dust as the cause of spots on Jupiter

TL;DR

This paper proposes that dust clouds produced by comet fragment impacts cause long-lived spots on Jupiter by affecting its light reflection and absorption, with a model predicting silicate spectral features.

Contribution

It introduces a model explaining Jupiter's spots as dust clouds from comet impacts, highlighting the role of silicate dust and its spectral signatures.

Findings

Dust clouds can explain the optical and longevity properties of Jupiter's spots.

Silicate dust should be detectable in the 10-micron spectral range.

Impact fragments larger than 0.4 km can produce sufficient dust for observed phenomena.

Abstract

The long-lived spots caused by the impact of fragments of Comet S-L 9 on Jupiter can be understood if clouds of dust are produced by the impact. These clouds reside in the stratosphere, where they absorb visible light that would ordinarily reflect from the cloud deck below, and reflect radiation at infrared wavelengths that would ordinarily be absorbed by atmospheric methane. Here we show that, provided that the nucleus of a fragment is composed substantially of silicates and has a diameter greater than about 0.4 km, dust in the required amounts will condense from the hot gas composed of cometary and Jovian material ejected from the site where the fragment entered, and the dust will be suspended in the stratosphere for long periods. Particles about 1$\;\mu$m in radius can explain both the optical properties and longevities of the spots. According to our model, a silicate band should be present in the $10 - \mu$m spectra of the spots.