英语听力：自然百科 Rho Ophiuchi Cloud 璀璨的星云

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The infrared¹ astronomical² satellite, now celebrating its 25th anniversary, gave us the first all sky view of our dusty infrared universe. Floating above the galactic center is the Rho Ophiuchi Cloud, about 400 light years away, it's one of the most spectacular nearby star-forming regions. NASA's Spitzer space telescope has now given us an impressive new view of this cloud's central core.

 

Compact yellow green arcs and filaments³ are shock fronts from proto-stellar jets within the cloud. These jets shoot out from young stars still growing as they gobble up the surrounding dust and gas. Here we see infrared light with wavelengths⁴ from 3.6 to 8 microns. Widening the coverage⁵ to include 24 microns yields an even richer array of colors that shed light on the temperature and composition of the dust here.

 

The cloud is named after the nearby star Rho Ophiuchi which ironically is not thought to be associated with the star-forming region, and does not appear in the Spitzer image. Also known as Lynds 1688, this region contains over 300 baby stars with ages of up to a few hundred thousand years. The dusty envelopes around the younger stars make them appear red in this rendering⁶. In visible light, they can't be seen at all, which is why astronomers⁷ rely on Spitzer's infrared perspective to help study the hidden universe.

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