Gravity gives the supernova its energy. For Type II supernovae, mass flows into the core by the continued formation of iron from nuclear fusion. Once the core has gained so much mass that it cannot withstand its own weight, the core implodes.
This implosion can usually be brought to a halt by neutrons, the only things in nature that can stop such a gravitational collapse.
Even neutrons sometimes fail depending on the mass of the star's core. When the collapse is abruptly stopped by the neutrons, matter bounces off the hard iron core, thus turning the implosion into an explosion. For a Type Ia supernova, the energy comes from the runaway fusion of carbon and oxygen in the core of a white dwarf. When the core is less massive than about 5 solar masses, the neutrons are successful in halting the collapse of the star creating a neutron star.
Neutron stars can sometimes be observed as pulsars or X-ray binaries. To understand the phenomenon of core collapse better, consider an analogy to a rocket escaping Earth's gravity.
According to Newton's law of gravity, the energy it takes to completely separate two things is given by:. When the rocket is shot off at a given velocity v , its energy is:. UTC Offset:. Picture of the Day Image Galleries. Watch : Mining the Moon for rocket fuel.
Queen guitarist Brian May and David Eicher launch new astronomy book. Last chance to join our Costa Rica Star Party! Learn about the Moon in a great new book New book chronicles the space program. Dave's Universe Year of Pluto. Groups Why Join? Astronomy Day. The Complete Star Atlas. Not all supernovae are created equal. Here is a brief description of the four main categories of exploding stars. Scientists classify Supernova a in the nearby Large Magellanic Cloud as a type II — meaning it resulted from the collapse, and ensuing explosion, of a massive star.
Challis and R. Kirshner Harvard-Smithsonian CfA. Supernovae are stars that suddenly increase drastically in brightness billions of times more luminous than the Sun , outshining their own galaxies.
They reach this brightness in just a few hours and take from weeks to months to fade. Scientists classify different types of supernovae by their emitted light signatures called spectra ; these show what elements the original star created and thus released into space after it exploded.
Once its mass reaches 1. Then, the carbon fuses, and the entire star explodes as a carbon-detonation supernova. The initial white dwarf can collect material from a company red giant star or from colliding with another white dwarf.
The star sheds material from its gaseous envelope late in its life hence the lack of hydrogen in its spectrum. The star then implodes, bounces back, and explodes. These monsters would have lived very short lives, detonating with an incomprehensible amount of energy. Type I are a little rarer, and are created when you have a very strange binary star situation.
One star in the pair is a white dwarf, the long dead remnant of a main sequence star like our Sun. The companion can be any other type of star, like a red giant, main sequence star, or even another white dwarf. When the stolen amount reaches 1. In a Type Ia supernova, a white dwarf left draws matter from a companion star until its mass hits a limit which leads to collapse and then explosion. Since they know how much energy it detonated with, astronomers can calculate the distance to the explosion.
There are probably other, even more rare events that can trigger supernovae, and even more powerful hypernovae and gamma ray bursts. These probably involve collisions between stars, white dwarfs and even neutron stars. Elements like ununseptium and ununtrium. It takes tremendous energy to create these elements in the first place, and they only last for a fraction of a second.
But in supernovae, these elements would be created, and many others.
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