(ORDO NEWS) — In astronomy, there are two terms for powerful stellar explosions – nova and supernova. In just three minutes, we will help you understand these concepts easily.
Nova – a thermonuclear explosion on the surface of a tiny but very dense star (white dwarf), which is part of a close binary system, where the role of the second stellar companion is played by a massive star (most often a red giant ).
During the close rotation of stars around a common center of mass, the white dwarf “steals” a part of the companion’s gaseous envelope saturated with hydrogen, which leads to the formation of an accretion disk.
At some point, the matter of the disk falls on the surface of the white dwarf, provoking a thermonuclear explosion.
At this moment, the luminosity of the white dwarf increases by a thousand, and sometimes even a million times!
After some time, the explosion repeats, and then another and another. It is impossible to predict an event of this kind.
It is noteworthy that the white dwarf not only survives such an explosion, but also warms up, which prolongs its life.
A supernova is a catastrophic collapse of the core of a massive star with the destruction of its gas shells, the remnants of which scatter through outer space at great speed.
In other words, a supernova is an explosion of a star that has reached the end of its evolutionary path, the initial mass of which was at least eight times the mass of the Sun.
- If the initial mass of the star is eight times the mass of the Sun, then after the explosion an incredibly dense neutron star is formed; with a diameter of only 10-20 kilometers, its mass is comparable to the mass of our luminary.
- If the initial mass of the star is 40 times the mass of the Sun, then a black hole is formed after the explosion.
A nova is a multiple event experienced by a tiny star in a close binary system, while a supernova is the final “chord” in the life of a massive star.
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