Using data from Parker Solar Probe, researchers saw impacts that were consistent with the two primary dust populations in the zodiacal cloud. The first population are grains being slowly pulled in toward the Sun over thousands to millions of years; then, as the swirling cloud gets denser, the larger grains collide and create fragments – called beta-meteoroids – that are pushed out of the solar system in all directions by pressure from sunlight.
Parker Solar Probe also picked up an enhancement in dust detections that didn’t match the two-component model, a tip that another dust population may be in the area. The researchers figured that a meteoroid streams – most likely the Geminids stream, which causes one of the most intense meteor showers at Earth – was colliding at high speeds into the inner zodiacal cloud itself. These impacts with zodiacal dust produce beta-meteoroids that don’t blast off in random directions, but are focused into a narrow set of paths.
This concept addresses a fundamental process that would be occurring not only at every meteoroid stream in our solar system, but with every meteoroid stream to varying degrees in every dust cloud in the universe.
Credit: NASA/Johns Hopkins APL/Ben Smith
Scientists using data from NASA’s Parker Solar Probe have assembled a comprehensive picture of the structure and behavior of the large cloud of space dust that swirls through the innermost solar system – and the new insight offers clues to similar clouds around stars across the universe.
Research teams led by Jamey Szalay of Princeton University and Anna Pusack of University of Colorado, Laboratory for Atmospheric and Space Physics took advantage of Parker Solar Probe’s flight path – an orbit that swings it closer to Sun than any spacecraft in history – to get the best direct look yet at the most active region of the zodiacal cloud, a dusty cloud of grains shed from passing comets and asteroids. The teams published their findings Sep. 9 in the Planetary Science Journal.
“Every stellar system has a zodiacal cloud, and we actually get to explore ours and understand how it works,” said Szalay. “Understanding the evolution and dynamics of our zodiacal cloud will allow us to better understand every zodiacal observation we’ve seen around any other stellar system.”
Built and operated by the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, Parker Solar Probe does not carry a dedicated dust counter that would give it accurate readings on grain mass, composition, speed and direction. But as dust grains pepper the spacecraft along its path, the high-velocity impacts create plasma clouds. These impact clouds produce unique signals in electric potential that are picked up by several sensors on the probe’s FIELDS instrument, which is designed to measure the electric and magnetic fields near the Sun.