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Anarchic region of star formation found in dust cloud

Source : ANI
Last Updated: Fri, May 03, 2013 09:30 hrs

Using the Danish Faint Object Spectrograph and Camera (DFOSC) on the Danish 1.54-meter telescope at European Southern Observatory's La Silla Observatory in Chile, astronomers have spotted an anarchic region of star formation inside an interstellar cloud.

NGC 6559 is a cloud of gas and dust located at a distance of about 5000 light-years from Earth, in the constellation of Sagittarius (The Archer).

The gas in the clouds of NGC 6559, mainly hydrogen, is the raw material for star formation. When a region inside this nebula gathers enough matter, it starts to collapse under its own gravity. The centre of the cloud grows ever denser and hotter, until thermonuclear fusion begins and a star is born. The hydrogen atoms combine to form helium atoms, releasing energy that makes the star shine.

These brilliant hot young stars born out of the cloud energise the hydrogen gas still present around them in the nebula. The gas then re-emits this energy, producing the glowing threadlike red cloud. This object is known as an emission nebula.

But NGC 6559 is not just made out of hydrogen gas. It also contains solid particles of dust, made of heavier elements, such as carbon, iron or silicon.

Known to astronomers as a reflection nebula, this type of object usually appears blue because the scattering is more efficient for these shorter wavelengths of light.

In regions where it is very dense, the dust completely blocks the light behind it, as is the case for the dark isolated patches and sinuous lanes to the bottom left-hand side and right-hand side of the image. To look through the clouds at what lies behind, astronomers would need to observe the nebula using longer wavelengths that would not be absorbed.

The Milky Way fills the background of the image with countless yellowish older stars. Some of them appear fainter and redder because of the dust in NGC 6559.

The Danish telescope has been in use at La Silla since 1979 and was recently refurbished to turn it into a remote-controlled state-of-the-art telescope. (ANI)




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