A cluster of stars, or comets?

This spectacular image produced by both ESO’s Atacama Large Millimetre/submillimetre Array (ALMA) in Chile and NASA's Hubble shows the glistening stars in the cluster Westerlund 1 and their comet-like characteristics. In some of the most giant stars in Westerlund 1 there appears to be comet-like ‘tails’ which are created by relentless winds forming

thick strands of material being carried outward.