…Rosetta’s comet!

For the last few months, comet 67P/CG has been behind the Sun from our vantage point on Earth, but it’s now back in the field of view of the European Southern Observatory’s Very Large Telescope.

Comet 67P/CG on 28 February 2014 by ESO's VLT. Credits: ESO/C. Snodgrass (Max Planck Institute for Solar System Research, Germany) & O. Hainaut (ESO)

Comet 67P/CG on 28 February 2014 by ESO’s VLT.
Credits: ESO/C. Snodgrass (Max Planck Institute for Solar System Research, Germany) & O. Hainaut (ESO)

The image presented here was taken on the night of the 27 February (09:30 GMT on 28 February). The image on the left was created by stacking individual exposures to show the background stars. These were then shifted to compensate for the motion of the comet, which appears as a small dot right on top of one of the stars (at the centre of the circle). The image on the right shows the comet when the star trails have been subtracted.

The observatory is collaborating with ESA to monitor the four kilometre-wide comet from the ground to help refine Rosetta’s navigation and to make assessments of the comet’s activity prior to the spacecraft’s arrival in August.

The comet is about 50% brighter than when it was last observed. Although it is also now nearer to Earth, it has brightened faster than expected for an inactive comet of this size, suggesting that its icy nucleus has started to evaporate as it moves gradually closer to the Sun.

The image is featured today as ESO’s Picture of the Week and ESA’s Space Science Image of the Week.