Related topics: massive stars · stars · white dwarfs · universe · dark energy

HSC16aay is a Type IIn supernova, study suggests

New research presented by an international team of astronomers suggests that a recently detected transient, designated HSC16aay, is a Type IIn supernova. A research paper reporting the discovery and detailing the finding, ...

Could this rare supernova resolve a longstanding origin debate?

Detection of a supernova with an unusual chemical signature by a team of astronomers led by Carnegie's Juna Kollmeier—and including Carnegie's Nidia Morrell, Anthony Piro, Mark Phillips, and Josh Simon—may hold the key ...

Active galaxies point to new physics of cosmic expansion

Investigating the history of our cosmos with a large sample of distant 'active' galaxies observed by ESA's XMM-Newton, a team of astronomers found there might be more to the early expansion of the universe than predicted ...

How hot are atoms in the shock wave of an exploding star?

A new method to measure the temperature of atoms during the explosive death of a star will help scientists understand the shock wave that occurs as a result of this supernova explosion. An international team of researchers, ...

High-speed supernova reveals earliest moments of a dying star

An international team of scientists, including astronomers from the Universities of Leicester, Bath and Warwick, have found evidence for the existence of a 'hot cocoon' of material enveloping a relativistic jet escaping a ...

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Supernova

A supernova (pl. supernovae) is a stellar explosion. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months. During this short interval, a supernova can radiate as much energy as the Sun could emit over its life span. The explosion expels much or all of a star's material at a velocity of up to 30,000 km/s (a tenth the speed of light), driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant.

Several kinds of supernovae exist that may be triggered in one of two ways, either turning off or suddenly turning on the production of energy through nuclear fusion. After the core of an aging massive star ceases to generate energy from nuclear fusion, it may undergo sudden gravitational collapse into a neutron star or black hole, releasing gravitational potential energy that heats and expels the star's outer layers. Alternatively, a white dwarf star may accumulate sufficient material from a stellar companion (usually through accretion, rarely via a merger) to raise its core temperature enough to ignite carbon fusion, at which point it undergoes runaway nuclear fusion, completely disrupting it. Stellar cores whose furnaces have permanently gone out collapse when their masses exceed the Chandrasekhar limit, while accreting white dwarfs ignite as they approach this limit (roughly 1.38 times the mass of the sun). White dwarfs are also subject to a different, much smaller type of thermonuclear explosion fueled by hydrogen on their surfaces called a nova. Solitary stars with a mass below approximately nine solar masses, such as the Sun itself, evolve into white dwarfs without ever becoming supernovae.

On average, supernovae occur about once every 50 years in a galaxy the size of the Milky Way. They play a significant role in enriching the interstellar medium with higher mass elements. Furthermore, the expanding shock waves from supernova explosions can trigger the formation of new stars.

Nova (plural novae) means "new" in Latin, referring to what appears to be a very bright new star shining in the celestial sphere; the prefix "super-" distinguishes supernovae from ordinary novae, which also involve a star increasing in brightness, though to a lesser extent and through a different mechanism. According to Merriam-Webster's Collegiate Dictionary, the word supernova was first used in print in 1926 and was coined by Swiss astrophysicist and astronomer, Fritz Zwicky.[citation needed]

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