2015년 2월 14일 토요일

[New post] Astronomy Photo of the Day: 2/14/15 — Barnard 92

New post on From Quarks to Quasars

Astronomy Photo of the Day: 2/14/15 — Barnard 92

by Jaime Trosper
Barnard 92
Image Credit: NASA/JPL-Caltech
This celestial region contains hundreds upon thousands of stars, appearing to represent each and every single color of the rainbow — all small, all beautiful, and all of them a small part of a much larger whole. In this case, that 'whole' is the Small Sagittarius Star Cloud, which can be found approximately 10,000 light-years from Earth in the Sagittarius constellation.
By far, the most dominant color in this field of view is black, only the darkness isn't the result of an absence of stars, but the overabundance of interstellar stellar dust. The dust in these black pockets — belonging to a second region, called Barnard 92 — is so thick, light from embedded stars simply can't break through, instead, it ricochets off grains of dust, effectively keeping the stars hidden from prying eyes. However, their loss is our gain.
As you can see, the contrast between the bright, colorful stars and the thick dust is rather beautiful. In fact, this might be one of the most dynamic dark nebulae in our galaxy (it's definitely among the first ever cataloged, found by famous astronomer Edward Emerson Barnard in 1919. He would go on to compile the most thorough, prolific catalog of 'dark objects' like Barnard 92, created to date), and it's all thanks to the Sagittarius Star Cloud (also called Messier 24).
The different colors correspond to temperature. This, in turn, gives us important information about the star's age and mass. The bluer the light, the younger and hotter the star is — ultimately, they live fast and die young. The red stars, on the other hand, are older and more evolved; our own Sun will share their fate here in a few billion years.

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