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Celestial Fireworks Celebrate Hubble's 25th Anniversary
Celestial Fireworks Celebrate Hubble's 25th Anniversary

This vibrant NASA Hubble Space Telescope image of young stars flaring to life is being released to celebrate Hubble's 25 years of exploring the heavens.

The sparkling centerpiece of this image is a giant cluster of about 3,000 stars called Westerlund 2. The cluster resides in a star-forming region known as Gum 29, located 20,000 light-years away in the constellation Carina.

The stellar nursery is difficult to observe, because it is surrounded by dust. However, Hubble's Wide Field Camera 3 peered through the dust in near-infrared light, giving astronomers a clear view of the region. Hubble's sharp vision resolves the dense concentration of stars in the central cluster, which measures about 6 to 13 light-years across.

The Westerlund 2 star cluster is only about 2 million years old and contains some of our galaxy's hottest, brightest, and most massive stars known. Some of the heftiest stars are carving deep cavities in the surrounding material by releasing a flow of ultraviolet light and gale-force stellar winds (streams of charged particles). The ultraviolet light and stellar winds are eating away the gas cloud in which the stars were born.

The image reveals a fantasy landscape of pillars, ridges, and valleys. The pillars, composed of dense gas, are resisting erosion from the fierce radiation and powerful winds. The pillars are a few light-years tall and point to the central cluster. They may be incubators for new stars. Other dense regions surround the pillars, including reddish-brown filaments of dense gas and dust.

Besides sculpting the gaseous terrain, the brilliant stars can also help create new generations of stars. For example, when stellar winds hit dense walls of gas, they create shocks, which may be generating a new wave of star birth along the wall of the cavity.

The red dots scattered throughout the image are a rich population of newly forming stars that are still wrapped in their gas-and-dust cocoons. These tiny, faint stars are between 1 million and 2 million years old and have not yet ignited the hydrogen in their cores to shine as stars. Hubble's near-infrared vision allows astronomers to identify them. The brilliant blue stars seen throughout the image are mostly foreground stars.

Westerlund 2 is named for Swedish astronomer Bengt Westerlund, who discovered the cluster in the 1960s.

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