Origin
The source of the dust has been long debated. Until recently, it was thought that the dust originated from the tails of active comets and from collisions between asteroids in the asteroid belt. Peter Jenniskens had previously recognized that many of our meteor showers have no known active comet parent bodies. In a 2010 article in the Astrophysical Journal, David Nesvorny and Peter Jenniskens attributed over 85 percent of the dust to occasional fragmentations of Jupiter-family comets that are nearly dormant. Jupiter-family comets have orbital periods of less than 20 years and are considered dormant when not actively outgassing, but may do so in the future. Nesvorny and Jenniskens' first fully dynamical model of the zodiacal cloud demonstrated that only if the dust was released in orbits that approach Jupiter, is it stirred up enough to explain the thickness of the zodiacal dust cloud. The dust in meteoroid streams is much larger, 300 to 10,000 micrometres in diameter, and falls apart in smaller zodiacal dust grains over time.
The Poynting-Robertson effect forces the dust into more circular (but still elongated) orbits, while spiralling slowly into the Sun. Hence a continuous source of new particles is needed to maintain the zodiacal cloud. Cometary dust and dust generated by collisions among the asteroids are believed to be mostly responsible for the maintenance of the dust cloud producing the zodiacal light and the gegenschein.
Particles can be reduced in size by collisions or by space weathering. When ground down to sizes less than 10 micrometres, the grains are removed from the inner solar system by solar radiation pressure. The dust is then replenished by the infall from comets. Zodiacal dust around nearby stars is called exozodiacal dust; it is a potentially important source of noise for directly imaging extrasolar planets. Nesvorny and Jenniskens have pointed out that this exozodiacal dust, or hot debris disks, can also help find planets, as planets tend to scatter the comets to the inner solar system.
Read more about this topic: Zodiacal Light
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