Cosmic Caterpillar

hubble-caterpillar_0This light-year-long stream of interstellar gas and dust sorta/kinda resembles a caterpillar. Harsh winds from extremely bright stars are blasting ultraviolet radiation at a wannabe star and sculpting the gas and dust into its long shape.

65 of the hottest, brightest known stars, classified as O-type stars are located 15 light-years away from the caterpillar, off the right edge of the image. Those stars and 500 or so less bright, but still highly luminous, B-type stars make up a group called the Cygnus OB2 association which is thought to have a mass more than 30,000 times that of our Sun.

The caterpillar-shaped knot, called IRAS 20324+4057, is a protostar in a very early stage of development. It’s still collecting material from the surrounding envelope of gas, but the envelope is being eroded by the radiation from Cygnus OB2. Protostars in this region should eventually become young stars with masses from one to ten times that of our Sun. However, if the eroding radiation from the nearby bright stars destroys the gas envelope before the protostars finish collecting mass, their their growth is stunted. Spectroscopic observations of the central star within IRAS 20324+4057 show that it is still collecting material quite heavily from its outer envelope, trying to bulk up.

Image Credit: NASA

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