Star Cluster NGC 602

In a nearby galaxy called the Small Magellanic Cloud, young stars are spewing radiation that's eating away at the cloud of gas and dust that gave birth to them not too long ago. This Hubble image, taken with the Advanced Camera for Surveys, shows that scene.

The cluster of blue stars, called NGC 602, formed when a large part of the gas cloud collapsed under gravity and became very dense. The fierce radiation now being produced by these hot, young stars is sculpting the inner rim of the gaseous nebula. Parts of the nebula resist this erosion better than others, leaving tall pillars that point toward the source of the radiation — the stars.

Because the Small Magellanic Cloud is relatively close to us — less than 200,000 light-years away — it gives astronomers a good opportunity to study star formation in a galaxy other than our own, where the conditions are different. It's also a dwarf galaxy, which has fewer stars and lacks the enriched gas that larger galaxies like ours have. So it could provide a glimpse at what star formation might have been like in the early universe, before the first generations of stars created and distributed heavier elements into the cosmic environment.

Using Hubble observations of NGC 602, a team of astronomers led by Lynn Redding Carlson of the Johns Hopkins University determined that the massive stars at the center of the cluster and other, less massive stars formed there about 4 million years ago. When Carlson and her colleagues used NASA's Spitzer Space Telescope to study NGC 602, they uncovered even younger stars, some still cloaked in gas and dust, at the outskirts of the cluster. Some of these stars appeared to have started forming only about a million years ago. The results suggest that star formation began in the center of the cluster and then worked its way outward.

Follow-up studies using Hubble observations, led by Guido De Marchi of the European Space Agency, confirmed that the stars of NGC 602 were not born all at once but at different times, finding that some star formation might have started there as far back as 60 million years ago.