Monday, December 5, 2011

'Murders star': the stars are a new way to die

This week has been known that Spanish researchers have discovered how a star induces another to the death a "murder stellar" set in just over half an hour and as a result of which creates a black hole with a mass slightly larger than the sun and a diameter of about 20 kilometers.

The journal Nature published the research, conducted by an international group led by Christina Ugarte Postigo Thöne and Antonio, the Institute of Astrophysics of Andalusia (Granada), in collaboration with Miguel Angel Aloy and Petar Mimica, the University of Valencia. In the same have found a plausible explanation to the puzzle proposed by the 'eruption of Christmas', a gamma-ray burst (GRB, for its acronym in English) of more than half an hour in length, which happened on December 25, 2010 .

This 'rash of Christmas' , or GRB101225A by scientific identification is the result of a neutron star merging with the helium core of a giant star and former, at a distance from Earth of about 5,500 million light-years . This "exotic" binary system went through a phase in which the neutron star entered the atmosphere of the giant companion star to reach its core is merged with it, the result being a huge explosion , initially invisible from Earth, and possibly the birth of a new black hole.

A massive star dies, forming a supernova, while it has been induced to death by his companion 's tremendous amount of energy released by the blast was channeled away from the center of the star at speeds approaching that of light.

As explained Miguel Angel Aloy, previously thought that most GRBs were associated with bigger stars than the Sun , which end up producing supernovae. But the 'eruption of Christmas', as Aloy, GRB is a "rare", with properties different from those known so far, and could be regarded as evidence that there is a new way of producing stellar black holes.

"A massive star dies , forming a supernova, while it has been induced to death by his companion, which has been falling far as the center of the star, which induces an unusual supernova explosion (in fact had not gone unnoticed be for the detection of the GRB) and a very compact object, possibly a black hole, "he stated.

Aloy noted that are common pairs of stars (binary systems) "but never seen live almost stellar this murder . " The most unusual property of this GRB is that it contains a "thermal contribution to the spectrum extremely powerful", and researchers believe that this thermal component is "a challenge to the well established paradigm that explains that the radiation emitted after the gamma-ray burst is in non-thermal (synchrotron). "

The gamma-ray bursts are flashes of radiation that can reach ultraintensa Earth from all directions of space. Phenomena are so powerful and energy that only one of them can be as bright as all the stars visible in the sky simultaneously, but only for a few seconds.

"This rash really blew everyone away and had plenty of anodyne properties, which motivated us to consider a wide range of possible explanations, including some related to the possibility that this was a rare event in our own galaxy, "said in a statement Petar Mimica.

For his part, Antonio Ugarte said that the fact that the same GRB afterglow is not watching a classic and a thermal component is detected hot supernova explosion so weak that there is no precedent of other equally, and gamma-ray activity as prolonged alerted us of their peculiar nature. "

"The classification of GRBs may have to be revised in light of these recent observations, according to which the stars seem to have found new ways to die , "the researchers conclude.


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