74 ASTRONOMY t FEBRUARY 2014
Multiple shells of gaseous material
form a cocoon around galaxy PGC
6240 in the southern constellation
Hydra. Distant galaxies litter the
background in this new Hubble
Space Telescope image. The object
holds interest for astronomers not
only because of its peculiar structure,
but also due to a cloud of numerous
globular star clusters orbiting it.
Unlike most globular clusters,
which contain old stars, PGC 6240
has clusters of varied ages. Astrono-
mers believe the unusual shelled
structure of PGC 6240 resulted from
two galaxies that merged, igniting
a recent burst of star formation in
the clusters.
A shelled
galaxy and
its clusters
FINALFRONTIER To the ends of the cosmos
ESA/HUBBLE/NASA