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Friday, January 20, 2012

Fine Structure Around Nebula Revealed

This is a new fact obtained about helix nebula. A picture of the nebula has been detected around. ESO VISTA telescope at Paranal Observatory in Chile, was successful in uncovering it.

ESO’s VISTA telescope, at the Paranal Observatory in Chile, has captured a striking new image of the Helix Nebula. This picture, taken in infrared light, reveals strands of cold nebular gas that are invisible in images taken in visible light, as well as bringing to light a rich background of stars and galaxies. (eso.org)

Basically, a star like the sun, have a supply of fuel with a certain amount. Through a nuclear reaction, the star then emit radiation to the whole space up to a certain period. Initially, the fuel of a star from a light element, Hydrogen. Then, through a nuclear reaction, the substance turns into heavier elements, Helium. The reaction continues, until finally produced heavier elements again. Unable to hold the outer layer, the stars slowly shed gas shells into the nebula. It has grown to become a white dwarf star. Helix Nebula is one example of the closest and most remarkable of a planetary nebula. It lies in the constellation Aquarius, about 700 light years from Earth. This strange object is formed when a star like the Sun are in the final stages of his life.

The nebula itself is a complex object composed of dust, ionised material as well as molecular gas, arrayed in a beautiful and intricate flower-like pattern and glowing in the fierce glare of ultraviolet light from the central hot star.

The main ring of the Helix is about two light-years across, roughly half the distance between the Sun and the nearest star. However, material from the nebula spreads out from the star to at least four light-years. This is particularly clear in this infrared view since red molecular gas can be seen across much of the image.

While hard to see visually, the glow from the thinly spread gas is easily captured by VISTA’s special detectors, which are very sensitive to infrared light. The 4.1-metre telescope is also able to detect an impressive array of background stars and galaxies.

The powerful vision of ESO’s VISTA telescope also reveals fine structure in the nebula’s rings. The infrared light picks out how the cooler, molecular gas is organised. The material clumps into filaments that radiate out from the centre and the whole view resembles a celestial firework display.

Even though they look tiny, these strands of molecular hydrogen, known as cometary knots, are about the size of our Solar System. The molecules in them are able to survive the high-energy radiation that emanates from the dying star precisely because they clump into these knots, which in turn are shielded by dust and molecular gas. It is currently unclear how the cometary knots may have originated.

Source: http://www.eso.org/public/news/eso1205/

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