Monday, July 15, 2013

Colorful imaged the death of a planetary nebula

The NASA has achieved through his telescope Chandra grasping the end of a star's life, namely NGC 2393, known as "Eskimo Nebula". This study allows astronomers to predict the demise of the Sun, expected within about 5,000 million years.

Planetary nebulae like this are formed when a star consumes all the hydrogen in its core, something will happen to our sun in about 5,000 million years, reports NASA. At the time this happens, 

the star passes to cool and then to expand, leading to increase in size. Then, the outer layers of the star are blown by the wind to about 50,000 miles per hour, leaving behind the hot core. The surface temperature of this core is about 50,000 ° C and ejects its outer layers with a wind more than six million miles per hour. The radiation from the star and the interaction of the fast wind with the slow wind filamentous membrane creates a planetary nebula. Eventually the remnant star collapses to form a white dwarf star.

The observations of NGC 2392 have been part of a study of three planets nebulae with hot gas at its core and in the images, it is possible to identify with the color purple. Chandra has identified elevated levels of X-rays in the star in question compared with the other two study carried.

The principal investigator has been Nieves Ruiz del Instituto de Astrofisica de Andalucia (IAA-CSIC) in Granada, who has enlisted the help of You-Hua Chu and Robert Gruendl of the University of Illinois, as well as Martin Guerrero, also of the Institute Astrophysics of Andalucía (IAA-CSIC), and Ralf Jacob, Matthias Steffen Detlef Schönberner and the Leibniz-Institut für Astrophysik Potsdam (AIP).

IAA-CSIC precisely explained in a press release that these planetary nebulae are a "beautiful example of interaction of stellar winds, where gas flows at different temperatures and speeds produce a characteristic structure: a central cavity consists of a very fast wind and hot a bright shell formed a dense, cold wind and an outer shell. "

Planetary nebulae, adds, "arising from the death of intermediate mass stars in the later stages, release of his jacket". The remaining stellar core, very hot, “produces ultraviolet radiation that ionizes the ejected material, which causes it to emit light." Cores also escape solar wind with a speed of thousands of kilometers per second. Nieves Ruiz explains: "This fast wind hits the outer, colder, dense, and spreading in the wind a shock that heats the gas inside the nebula and produces the emission of X-ray energy in planetary nebulae."

So far, the samples of planetary nebulae have soft X-ray emission and conductive layer "was reduced to an object, the Cat's Eye Nebula, so it was not known whether that layer was actually driving a common element in nebulae

The data were consistent in two of the three nebulae, but in NGC 2392 detected "serious discrepancies" central star "does not generate enough wind energy in order to produce X-rays (which, however, they are detected) and the bubble expands to ninety miles per second, more than twice the average speed similar objects ". 

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