European Space Agency's Rosetta mission is succeeding in their mission to follow the life cycle of a comet, according to a press release by the agency. Comet 67P/Churyumov-Gerasimenko is shedding four years of dust accumulation and the COmetary Secondary Ion Mass Analyzer (COSIMA) is collecting, analyzing, measuring and imaging the particles.
The journal Nature has published the results of the tests conducted from August 2014, when the probe landed, until October 2014.
The dust particles were not icy, but rich in sodium, which is a characteristic of "interplanetary dust particles," according to ESA. "These are found in meteor streams originating from comets, including the annual Perseids from Comet 109P/Swift-Tuttle and the Leonids from 55P/Tempel-Tuttle."
"We found that the dust particles released first when the comet started to become active again are 'fluffy.' They don't contain ice, but they do contain a lot of sodium," lead author Rita Schulz of ESA's Scientific Support Office said. "We have found the parent material of interplanetary dust particles."
Scientists think the dust coat shedding is from the comet's last perihelion passage when gas flow had quieted down. The comet was "drying out," according to ESA.
"We believe that these 'fluffy' grains collected by Rosetta originated from the dusty layer built up on the comet's surface since its last close approach to the Sun," said Martin Hilchenbach, COSIMA principal investigator at the Max-Planck Institute for Solar System Research in Germany. "This layer is being removed as the activity of the comet is increasing again. We see this layer being removed, and we expect it to evolve into a more ice-rich phase in the coming months."
Comet 67P/C-G should be at its closest point to the sun in August. As it warms, dust will dry and the comet will shed the layer.
"In fact, much of the comet's dust mantle should actually be lost by now, and we will soon be looking at grains with very different properties," Schulz said.
"Rosetta's dust observations close to the comet nucleus are crucial in helping us to link together what is happening at the very small scale with what we see at much larger scales, as dust is lost into the comet's coma and tail," said Matt Taylor, ESA's Rosetta project scientist. "For these observations, it really is a case of 'watch this space' as we continue to watch in real time how the comet evolves as it approaches the Sun along its orbit over the coming months."
