Rosetta’s comet is waking up

On 20 January 2014, ESA's Rosetta spacecraft emerged from a long deep-space hibernation to approach its target — comet 67P/Churyumov-Gerasimenko (67P/CG).

From our vantage point on Earth, comet 67P/CG has only just reappeared from behind the Sun. On 28 February 2014 ESO's Very Large Telescope (VLT) directed its gaze towards the comet as soon as it became visible from ESO's Paranal Observatory in Chile. ESO is collaborating with ESA to monitor the comet from the ground as it is approached by Rosetta over the coming months. These observations will prepare for the spacecraft's major rendezvous with the comet, planned for August of this year (see potw1403a).

This new image, and many more to come, will be used by ESA to refine Rosetta's navigation, and to monitor how much dust the comet is releasing. The image on the left was created by stacking the individual exposures to show the background stars — they were then shifted to compensate for the motion of the comet, which appears as a small dot right on top of one of the star trails (at the centre of the circle). The image on the right shows the comet with the stars subtracted out.

This new image shows a brightening of the comet, indicating that the ice at its heart has started to evaporate as it warms up in its approach to the Sun. Just like the Rosetta spacecraft, the comet itself is emerging from hibernation.

Links

• ESA information on Rosetta
• ESO's Very Large Telescope