The Rosetta Comet Has Developed A Coma

The comet that is the destination of the ESA's Rosetta spacecraft has begun to reveal its true personality. This timelapse image of 67P/Churyumov–Gerasimenko shows its dusty veil, the "coma," expanding as it gets nearer to the sun.

The sequence of images was taken between March 27 and May 4, as the gap between the European Space Agency's craft—launched a decade ago—and the comet has closed from around 5 million km to 2 million km.

By the end of the sequence, the comet's coma extends some 1,300 km into space. By comparison, the nucleus is only around 4 km across.

The coma has developed as a result of the comet moving progressively closer to the sun along its 6.5 year orbit. Even though it is still more than 600 million km from the sun— more than four times the distance between the Earth and the sun—it has already started to warm, causing its surface ices to sublimate and gas to escape from its rock-ice nucleus.

As the comet continues to move closer to the sun, pressure from the solar wind will eventually cause some of the material to stream out into a long tail.

Rosetta will rendezvous with the comet in August and deploy a lander to its surface in November.

Source: ESA