
On February 19, 2016 Rosetta’s instruments detected an outburst event from Comet 67P/Churyumov–Gerasimenko. The source was traced back to a location in the Atum region, on the comet’s large lobe, as indicated in this image.
Credit: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0
The European Space Agency’s Rosetta comet orbiter has caught on camera an outburst from the celestial wanderer.
According to an ESA press statement today, Rosetta unexpectedly captured a dramatic comet outburst that may have been triggered by a landslide.
Nine of Rosetta’s instruments, including its cameras, dust collectors, and gas and plasma analyzers, were monitoring the comet from about 35 km in a coordinated planned sequence when the outburst happened on February 19th.
Outburst signatures
Rosetta’s OSIRIS wide-angle camera captured the outburst from the Atum region on Comet 67P/Churyumov–Gerasimenko’s large lobe.
Over a two hour period, Rosetta recorded outburst signatures that exceeded background levels in some instruments by factors of up to a hundred.
Astronomers on Earth also noted an increase in coma density in the days after the outburst.
Landslide
“The fact that the outburst started when this area just emerged from shadow suggests that thermal stresses in the surface material may have triggered a landslide that exposed fresh water ice to direct solar illumination,” explains ESA. “The ice then immediately turned to gas, dragging surrounding dust with it to produce the debris cloud seen by OSIRIS,” the press statement adds.
What’s ahead?
Rosetta was launched in 2004, catching up with the comet 67P/Churyumov-Gerasimenko ten years later.
On November 12, 2014, the orbiter released the Philae probe that repeatedly bounced across the comet then came to a full-stop to relay science data.

This series of 19 images, acquired by the Rosetta orbiter’s Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) on 12 November 2014, shows the Philae lander during its descent towards Comet 67P/Churyumov-Gerasimenko.
Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
The Rosetta orbiter is set to complete its mission in a controlled descent to the surface of its comet on September 30th.
Next month’s descent will enable Rosetta to make up-close measurements, including very-high-resolution imaging.
Communications will cease, however, once the orbiter reaches the surface, and its operations will then end.
The target region for Rosetta’s impact is still under discussion. It is expected that Rosetta’s impact will take place at about 1 mile per hour (50 centimeters per second).
For a ring side seat to the outburst, go to:
http://www.esa.int/spaceinimages/Images/2016/08/Comet_outburst