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> Open cluster Westerlund 2 in Carina
Open cluster Westerlund 2 in Carina
author: Nasa/ESA/Novapix
reference: a-aou98-00320
Image Size 300 DPI: 75 * 56 cm
The sparkling centerpiece of this image taken by the Hubble space telescope is a giant cluster of about 3,000 stars called Westerlund 2, named for Swedish astronomer Bengt Westerlund, who discovered the grouping in the 1960s. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20,000 light-years away from Earth in the constellation Carina.
To capture this image, Hubble’s near-infrared Wide Field Camera 3 near-infrared pierced through the dusty veil shrouding the stellar nursery, giving astronomers a clear view of the nebula and the dense concentration of stars in the central cluster. The cluster measures between 6 to 13 light-years across.
The giant star cluster is only about 2 million years old and contains some of our galaxy’s hottest, brightest, and most massive stars. Some of its heftiest stars unleash torrents of ultraviolet light and hurricane-force winds of charged particles that etch at the enveloping hydrogen gas cloud.
The nebula reveals a fantasy landscape of pillars, ridges, and valleys. The pillars, composed of dense gas and thought to be incubators for new stars are a few light-years tall and point to the central star cluster. Other dense regions surround the pillars, including reddish-brown filaments of gas and dust.
The brilliant stars sculpt the gaseous terrain of the nebula and help create a successive generation of baby stars. When the stellar winds hit dense walls of gas, the shockwaves may spark a new torrent of star birth along the wall of the cavity. The red dots scattered throughout the landscape are a rich population of newly forming stars still wrapped in their gas-and-dust cocoons. These tiny, faint stars are between 1 million and 2 million years old — relatively young stars — that have not yet ignited the hydrogen in their cores. The brilliant blue stars seen throughout the image are mostly foreground stars.
Because the cluster is very young — in astronomical terms — it has not had time to disperse its stars deep into interstellar space, providing astronomers with an opportunity to gather information on how the cluster formed by studying it within its star-birthing environment.
The image’s central region, which contains the star cluster, blends visible-light data taken by Hubble’s Advanced Camera for Surveys with near-infrared exposures taken by the Wide Field Camera 3. The surrounding region is composed of visible-light observations taken by the Advanced Camera for Surveys. Shades of red represent hydrogen and bluish-green hues are predominantly oxygen.
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