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Dying stars tend to come out with an explosion, producing spectacular flashes of light visible in our night sky. NASA photographed here a distant white dwarf star making its appearance in what is called a "classic nova". White Dwarves represent the very last stage in the life cycle of a dying star and form the core of a star with no fuel. According to NASA, white dwarfs are usually born from low to medium mass stars, like our Sun.
And sometimes, white dwarves will spontaneously explode into so-called classic nova like the one in NASA's photo.
NASA said, "This object has become sensational in the astronomical community when a team of researchers pointed it with our Chandra X-ray telescope in 1901, noting that it had suddenly appeared as the One of the brightest stars in the sky for a few days. , before gradually fading into brightness.
"Today, astronomers cite it as an example of a" classic nova ", an explosion produced by a thermonuclear explosion on the surface of a white dwarf star, the dense remnant of a star like that of the Sun. "
The object in question is GK Persei or Nova Persei 1901 – a brilliant nova that was produced in 1901.
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The cosmic explosion was first discovered in February 1091 by a Scottish cleric named Thomas David Anderson.
The explosion was discovered in the Perseus constellation and until 1918, it was the brightest nova to illuminate the sky above the Earth.
But what prompted the white dwarf star to burn so dramatically in the first place?
The team behind NASA's Chandra telescope explained: "A nova can occur if the high gravity of a white dwarf pulls material from its companion star into orbit.
"If enough material, mainly in the form of gaseous hydrogen, accumulates on the surface of the white dwarf, nuclear fusion reactions can occur and intensify, resulting in a bomb explosion. with hydrogen of cosmic size.
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"The outer layers of the white dwarf are blown, producing an explosion of nova that can be observed for several months, or even years, as the material expands in space."
In some ways, scientists consider classic novae as the smallest cousins of supernova explosions.
Supernovas are considerably larger eruptions of whole stars, which are momentarily so bright that they can overshadow their host galaxy.
In both cases, however, both novae produced powerful shock waves that propagate in space at hypersonic velocities.
The explosion of the nova has been estimated at around 700 000 km / h.
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NASA's Chandra telescope observed GK Persei for the first time in 2000, followed by new observations in 2013.
The 13-year interval between observations gave NASA enough time to observe the evolution of the nova.
Chandra's team said, "A fascinating discovery shows how the study of Nova remains can provide important clues to the environment of the explosion.
"The X-ray luminosity of the GK Persei residue decreased by about 40% over the 13 years that elapsed between Chandra's observations, while the temperature of the gas in the residue remained almost constant, at about one million degrees Celsius. "
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