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NGC 7822 - Racing to Form Stars
Star formation is quite common in the disk of a spiral galaxy like the Milky
Way. In regions where very massive stars form, their intense energy output
heats the surrounding gas and can actually influence whether stars can form
around them. This image of the star-forming region NGC 7822 was taken with a
filter that passes a narrow range of colors to highlight emission from
hydrogen gas excited by the intense energy output of a massive star in the
region, like the one in the image.
Prominent in theimage are two darker structures that are made of cooler,
dense hydrogen gas. Bright rims on the edges of these structures trace the
interface regions between the hot and cold gas phases. Astronomers are very
interested in these interface regions, as shocik waves propagating into these
regions can cause material to collect and perhaps form new stars there.
However, the same massive stars can also disrupt star formation. If the cold
material is heated too quickly, then there will not be enough time for
material to collect to form new stars and the dense gas will just diffuse back
Interrestingly, most of the stars in our Galaxy, including our Sun, probably
formed in an environment similar to this one with nearby very massive stars.