IC349 and Merope

In the famous Pleiades star cluster, a star's light slowly destroys a passing cloud of gas and dust. The star, Merope, lies just off the upper right edge of this image taken by the Hubble Space Telescope.
The cloud, known as IC 349, and the star have been in existence for millions of years. In the past 100,000 years, however, part of the cloud has by chance moved so close to the star - only 3,500 times the Earth-Sun distance - that the star's light affects the cloud's dust in an unusual manner.
Pressure of the star's light significantly repels the dust in the reflection nebula with smaller dust particles being repelled more strongly. Eventually parts of the dust cloud have become stratified and point toward Merope, with the closest particles being the most massive and so the least affected by the radiation pressure. A longer term result is the general destruction of the dust by the energetic starlight.
Image credit: NASA/STScI/George H. Herbig and Theodore Simon (IfA, U. Hawaii)

Tarantula Nebula

In the center of star-forming region 30 Doradus lies a huge cluster of the largest, hottest, most massive stars known. These stars, known as the star cluster R136, and part of the surrounding nebula are captured here in this gorgeous visible-light image from the Hubble Space Telescope. Gas and dust clouds in 30 Doradus, also known as the Tarantula Nebula, have been sculpted into elongated shapes by powerful winds and ultraviolet radiation from these hot cluster stars. The 30 Doradus Nebula lies within a neighboring galaxy, the Large Magellanic Cloud, located a mere 170,000 light-years away.
Image credit: NASA, J. Trauger (JPL), J. Westphal (Caltech)

The Snowflake Cluster and the Cone Nebula

Strange shapes and textures can be found in the neighborhood of the Cone Nebula. These patterns result from the tumultuous unrest that accompanies the formation of the open cluster of stars known as NGC 2264, the Snowflake Cluster. To better understand this process, a detailed image of this region was taken in two colors of infrared light by the orbiting Spitzer Space Telescope.
Bright stars from the Snowflake Cluster dot the field. These stars soon heat up and destroy the gas and dust mountains in which they formed. One such dust mountain is the famous Cone Nebula, visible in the above image on the left, pointing toward a bright star near the center of the field. The entire NGC 2264 region is located about 2,500 light years away toward the constellation of the Unicorn (Monoceros).
Image credit: NASA

Star Cluster RCW 38

A mere 6,000 light-years distant and sailing through the constellation Vela, star cluster RCW 38 is full of powerful stars. It's no surprise that these stars, only a million years young with hot outer atmospheres, appear as point-like sources dotting this x-ray image from the orbiting Chandra Observatory.
But the diffuse cloud of x-rays surrounding them is a bit mysterious. The image is colour coded by x-ray energy, with high energies in blue, medium in green and low energy x-rays in red. Just a few light-years across, the cloud, which pervades the cluster, has colours suggesting the x-rays are produced by high energy electrons moving through magnetic fields. Yet a source of energetic electrons, such as shockwaves from exploding stars (supernova remnants) or rotating neutron stars (pulsars), is not apparent in the Chandra data. Whatever their origins, the energetic particles could leave an imprint on planetary systems forming in young star cluster, just as nearby energetic events seem to have affected the chemistry and isotopes found in our own solar system.
Image credit: NASA