White dwarf to the supernova

A team of US researchers analyzed X-ray data of the supernova remnant known as 3C 397 collected by the telescope Suzaku. The results indicate that the explosion, which took place thousands of years ago, was triggered by a single white dwarf.
Using the archive data from X-ray satellite Suzaku, astronomers were able to determine the mass of a white dwarf exploded thousands of years ago. The results clearly indicate the explosion of a single white dwarf, excluding the scenario well established that involves a pair of white dwarfs in coalescence. The work was published in The Astrophysical Journal Letters.
“Several lines of evidence indicate that both of these mechanisms produce what we call Type Ia supernovae,” said researcher Hiroya Yamaguchi, an astrophysicist at the Goddard Space Flight Center in Greenbelt NASA. “To understand how these stars explode, we have to study the debris in detail with sensitive instruments such as those aboard Suzaku.”


Credit: NASA/Suzaku e NASA/CXC, DSS, e NASA/JPL-Caltech

The researchers analyzed the observations archive of supernova remnant called 3C 397, which is located about 33,000 light-years away from us in the constellation Aquila. Astronomers estimate that this cloud of stellar debris is expanding from a time ranging from 1,000 to 2,000 years. 3C 397 is therefore a remnant stellar middle-aged.
The team found very clearly the presence of crucial elements to estimate the weight of the white dwarf and the data were obtained using the imaging spectrometer aboard Suzaku. The observation was made in October 2010 in an energy range between 5,000 and 9,000 electron volts, and reached a total exposure of 19 hours effective.
The data in the infrared band obtained from NASA’s Spitzer Space Telescope have also provided information on the amount of gas and dust collected from the cloud while expanding into interstellar space. The observations made in April 2005 indicate that 3C 397 has collected a mass of about 18 times that of the original white dwarf.
Most of the small and intermediate mass stars, like the Sun, will end their days as white dwarfs. A typical white dwarf is massive as our Sun, and has more or less the size of a terrestrial planet. This makes white dwarfs between objects denser you know, surpassed only by neutron stars and blacks holes.
“White dwarfs are stable until they reach the weight of about 1.4 solar masses,” said Carles Badenes, professor in the Department of Physics and Astronomy, University of Pittsburgh in Pennsylvania. “The white dwarfs that are close to this weight limit are on the brink of catastrophic explosion. All you need is the triggering a bit ‘more mass. ”
Until recently, astronomers believed that the most likely channel through which a white dwarf could increase its mass was getting material from a companion similar to the Sun, in a close binary system. Accumulating matter from its companion, in the course of millions of years, the white dwarf can gradually approach the weight limit, until they explode. We expect that the companion stars survive the explosion, but astronomers have found little evidence of their presence, and this indicates the need for an alternative model. In the scenario of coalescence, the explosion is triggered by a pair of white dwarfs with mass less than the critical one, whose orbits shrink over time to ensure that the two stars are based and explode.
“With the count of nickel and manganese in the expanding cloud, we are able to distinguish which of these scenarios is responsible for a supernova remnant,” said Brian Williams of Goddard astrophysicist. “The explosion in a single white dwarf near the limit of its mass and a merger of two white dwarfs in fact produce significantly different quantities of these elements.” The team also measured the iron and chromium present in the cloud since these are elements that are produced in all type Ia supernovae and allow us to standardize the calculations.

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