BIGGEST STAR GALAXY ranked in the COCOON

02.12.2003

 

BIGGEST STAR GALAXY ranked in the COCOON

02.12.03, the


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Since 1841, when the long is no different southern star This Dogs (Eta Carinae) experienced a bright flash, astronomers have puzzled over what was happening to her. However, an impressive distance of luminaries — 7,500 light years — hurt see the details of what is happening. It is known that the star is surrounded by Homunculus Nebula — two mushroom-shaped cloud ejected a star, and every cloud is a hundred times more than the solar system.

Only now infrared interferometry has allowed an international team of scientists using the VLT telescope to look inside the stellar wind. According to Roy's background Buckel, stellar wind Eta dogs proved to be extremely elongated and the star itself — is very unstable due to too rapid rotation.

Dogs of this, the brightest star in our galaxy, by all standards is a real monster: it is a hundred times larger than the sun and five million times brighter. This star is in the last stage of his life, and therefore it is very unstable. From time to time it occurs giant flare, one of which occurred in 1841 and led to the emergence of a beautiful bipolar nebula known as the Homunculus Nebula. Then, despite the long distance, Dogs This is the second brightest star in the sky, second only to Sirius.






Each of these clouds is several hundred times larger than the entire solar system

The star is so large that its outer layers are constantly being carried into space by radiation pressure — the effects of photons on atoms of gas. Thus lose weight many stars, including the sun, but in the case of Eta Dogs losses are so large (about 500 Earth masses per year), which is very difficult to find the boundary between the outer layers of the star and the surrounding stellar wind.

With the help of infrared instruments VLT telescope for the first time scientists were able to determine the approximate shape of the stellar wind. Pictures showed that in the middle of the Homunculus Nebula is dominated by a point source of light with many colorful "bubbles" in the immediate vicinity. Observations using interferometry brought a real surprise — they have shown that the wind Eta Dogs are surprisingly uniform: one axis and a half times longer than the other. And the longer axis coincides with the direction of the larger mushroom-shaped cloud. The scientists were even able to detect the boundary where the stellar wind becomes so dense that it ceases to be transparent to the agent. By the way, the stellar wind is also stronger in the direction of the longer axis.






The intensity of the stellar wind of Eta Dogs extremely uneven

According to generally accepted theories, the star loses most of its mass at the equator. It is here that the stellar wind is "reinforcement" of the centrifugal force generated by the rotation of the star. However, if the theory was valid in this case, the axis of rotation would be perpendicular to both mushroom cloud. But then the clouds could not be located as the spokes of the wheel relative to the rotating star, and the substance has been thrown out in 1841, stretched out as if in a circle or a torus.

The fact that scientists have observed, is only possible if the stellar wind from Eta Dogs "pulled" toward the poles. The basic assumption of the authors observation is that the star is located far away in the depths of the stellar wind, is flattened at the poles. Then poles are closer to the center of the star, where the fusion reaction, and therefore is heated to higher temperatures. Then, the radiation pressure is higher also in the direction of the poles, and the outer layers in this field will be "blown out" is stronger than the outer layers at the equator.

Based on this model, the researchers calculated the speed of rotation of the star. It proved to be 90% of maximum (where the failure occurs star). Now she loses stuff so fast that could completely disappear in 100,000 years. More likely, however, is different: the star will disappear long before the explosion of a supernova, which will be visible even in daylight with the naked eye. It will happen soon enough in astronomical terms — 10-20 thousand years.

 

 

 

 

 

 

 

 

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