Astrophotographer Jacint Roger has spotted a small object in a sequence of images of 67P/Churyumov-Gerasimenko taken by ESA’s Rosetta spacecraft on October 21, 2015. At that time, the spacecraft was at over 250 miles (400 km) away from the comet’s center. The Rosetta team is now looking into this large piece of cometary debris in greater detail.
Comet 67P/Churyumov-Gerasimenko and Churymoon (circled). Image credit: ESA / Rosetta / MPS / OSIRIS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA / J. Roger.
“As 67P/Churyumov-Gerasimenko neared its closest approach to the Sun in July and August 2015, instruments on Rosetta recorded a huge amount of dust enshrouding the comet,” Rosetta scientists said.
“This is tied to the comet’s proximity to our parent star, its heat causing the comet’s nucleus to release gases into space, lifting the dust along.”
“A single image from Rosetta’s OSIRIS narrow-angle camera can contain hundreds of dust particles and grains surrounding the 2.5-mile (4 km) wide nucleus of 67P/Churyumov-Gerasimenko.”
Dubbed Churymoon, the newly-discovered object is likely the largest chunk detected around the comet, and will be subject to further investigations.
The chunk is approximately 13 feet (4 m) in diameter, according to the Rosetta researchers.
“Modeling of the Rosetta images indicates that Churymoon spent the first 12 hours after its ejection in an orbital path around the comet at a distance of between 1.5 and 2.4 miles (2.4-3.9 km) from the comet’s center,” they said.
“Afterwards, the object crossed a portion of the coma, which appears very bright in the images, making it difficult to follow its path precisely.”
“However, later observations on the opposite side of the coma confirm a detection consistent with the orbit of the chunk, providing an indication of its motion around the comet until October 23, 2015.”
