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A dramatic structure of arched, ragged filaments decorates this Hubble Space Telescope view of one of the most dynamic and intricately detailed star-forming regions in space. A ridge of material gently cradles a star cluster in its center. The cluster, known as NGC 346 is located 210,000 light-years away in the Small Magellanic Cloud (SMC), a satellite galaxy of our Milky Way.

A torrent of radiation from the cluster's hot stars eats into denser areas creating a fantasy sculpture of dust and gas. The dark, intricately beaded edge of the ridge, seen in silhouette by Hubble, is particularly dramatic. It contains several small dust globules that point back towards the central cluster, like windsocks caught in a gale.

Energetic outflows and radiation from hot young stars are eroding the dense outer portions of the star-forming region, formally known as N66, exposing new stellar nurseries. The diffuse fringes of the nebula prevent the energetic outflows from streaming directly away from the cluster, leaving instead a trail of filaments marking the swirling path of the outflows.

The NGC 346 cluster, at the center of this Hubble image, is resolved into at least three sub-clusters and collectively contains dozens of hot, high-mass stars, more than half of the known high-mass stars in the entire SMC galaxy. A myriad of smaller, compact clusters is also visible throughout the region.

Some of these mini-clusters appear to be embedded in dust and nebulosity, and are sites of recent or ongoing star formation. Much of the starlight from these clusters is muted by local dust concentrations that are the remnants of the original molecular cloud that collapsed to form N66. This image of NGC 346 and its surrounding star formation region was taken with Hubble's Advanced Camera for Surveys in July 2004. The image appears in black and white to show the dramatic structure of this pure Hubble filter - Halpha (pronounced H alpha) - which constrains light that is only emitted from doubly ionized hydrogen. In star forming regions, this filter is particularly useful in showing detail and structure from gas and dust.
See color images of NGC 346 and its environment.

Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
Acknowledgment: A. Nota (STScI/ESA)