Newly released images taken by NASA's Hubble Space Telescope in July 1997 show star formation occurring in a galaxy that is relatively close to Earth.
The image shows the evolution of dust and gas to stars and clusters in the galaxy NGC 4214, about 13 million light years from Earth. A light year is 6 trillion miles.
The galaxy is dense with faint stars, but dominated by clouds of glowing gas around bright stellar clusters.
The youngest of these star clusters is shown at the lower right of the picture, where they appear as about half a dozen bright clumps of glowing gas.
Young stars have a whitish to bluish color in the Hubble image, because of their high surface temperatures, ranging from 10,000 up to about 50,000 degrees Celsius.
The young stars also eject fast "stellar winds," moving at thousands of miles per second, which plow out into the surrounding gas.
The center of the image shows a cluster of hundreds of massive blue stars, each of them more than 10,000 times brighter than our sun.
The cluster is surrounded by a heart-shaped bubble inflated by combined stellar winds and radiation pressure.
A vast heart-shaped bubble, inflated by the combined stellar winds and radiation pressure, surrounds the cluster. The expansion of the bubble is augmented as the most massive stars in the center reach the ends of their lives and explode as supernovae.
Deprived of gas, the cluster at the center of NGC 4214 will be unable to form further new stars, and its luminous stars will continue to explode as supernovae and disappear.
Elsewhere in the galaxy, however, gas will start to collapse and form yet another new generation of stars, even as the clusters visible now gradually fade away.
The faint stars throughout the picture are much older than the bright blue supergiants, and show that episodes of star birth have been occurring in NGC 4214 for billions of years.
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