How do the 2 types of supernovae differ? What kind of star gives rise to each type?

Answer 1

Type II is the "normal" type of supernova.

It occurs when a giant star uses up it's fuel. In a large star, a chain of fusion events allows the star to use it's fuel over and over. It's hydrogen is turned to Helium, then the Helium is turned to Carbon, and so on.

However, this all stops when the star gets to Iron. Iron fusion can still happen, but the problem is that no fusion reaction involving Iron produces energy; they all use up some energy of the star. This means that the Iron core of the star no longer provides outward pressure, and the core is squeezed harder and harder until all the atomic nuclei are touching.

Then the gas "bounces" away from the core. Normally this would not be enough to make the star explode but the core also releases a burst of neutrinos as the protons in the core become neutrons. So the outer layer explodes outward, leaving the neutron core at the center. The core that is left over is called a "Neutron Star," unless the star was very large (at least 20 times the mass of the sun) in which case the core becomes a black hole.

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Type I happens under different circumstances. Essentially a type I supernova always involves binary stars.

Type Ia (which I believe is the most common of the type I's) involves a white dwarf star orbiting a large star like a red giant very closely. Since the white dwarf is very dense, it "steals" gas from the other star through gravity - that gas is pulled away from the surface of the giant star and spirals in to the white dwarf.

When the white dwarf accretes enough matter, the pressure of that matter sparks a carbon fusion reaction (since white dwarfs are made of carbon). This reaction is so sudden that it blows the white dwarf apart in a massive shockwave.

Type Ib and Ic also exist where a star that is not a white dwarf is under similar circumstances. Like the white dwarf the star must have lost much if not most of its outer layers (either because of solar wind or a neghbouring star), and then begins to accrete mass from a larger companion. However, though in formation the type Ib and Ic bear more similarity to type Ia, the mechanics of the explosion is more similar to that of type II.

Answer 2

The distinction between type I and type II supernovae is that type II have hydrogen in their spectra, while type I do not.

Type II supernovae are the result of core collapse in massive stars; the hydrogen comes from the outer envelope of the star. A neutron star or black hole may be left.

Type Ia are from white dwarfs that accumulate enough extra material from a companion star to reignite fusion. The entire star reacts at once, causing a massive explosion that completely destroys the star. Types Ib and Ic are from collapsing stars, like type II. They lack hydrogen because the star has blown off its outer layers, leaving only a super-hot core.

Answer 3

Massive stars and super massive stars. The former, in its final stage of life collapses into a neutron star, the results of this collapse is a nova. The latter has enough mass and gravitational energy to cause a horrendous explosion and a rebound effect that blows the outer shells of the mass into space in the form of elements heavier than iron. The amount of energy released outshines the stars in the galaxy and the shock wave can destroy a large percentage of the galaxy, this event is called a super nova, a black hole may be created in the process.

Answer 4

The lifecycle of stars
The Orion nebula. Cloud of mainly Hydrogen + Helium
The Orion nebula is large and full of gas and stars that are lightened by young stars. The cloud contains mainly hydrogen and helium.
source: US naval obsorvatory In the enormous space between the stars large dust nebulae exist, that consist of gas molecules and dustparticles. These clouds are very thin but still stars are formed of them.

The birth of a star.
A star is formed when matter in the clouds clump together, through which the clouds gets more dense. This packing occurs under the influence of stars in the neighborhood, these bring about strong ionization, as well as shockwaves. The matter is compressed by this and slowly kernels are formed of more packed up dustparticles of which the gravitational forces increase. While the density of the dustkernels get higher, the clouds collaps more and more. This proces generates energy, that heats up the dust and (mainly hydrogen) gas. Finally so much heat is generated that the gas and dustparticles start to glow. Now a protoster is formed.

Inside the nucleus of the protoster the matter is heated up. The temperature goes slowly up to millions Kelvin. When it reachess a temperature of 10 million Kelvin, nuclearfusion reaction are started in the gas. The hydrogen atoms are fused to helium, and from this lots of energy is released.
This energy is moving from the nucleus towards the outerlayers and is emitted into space as radiation of heat and light. The outer layers of the star are still pressed inside by gravity. The energy coming from the inner parts of the star heats up the gasses, which causes pressures to the outside. After a while the gravity forces and the gaspressure are balanced out, the star is not further compressed. In this steady stade it became a main star.


A star in steady state Lifetime depends on the size.
The size, the surface temperature and the energy the star emits remains the same for a very long period. A star remains in the steady stade as long as the gases contain hydrogen, after it runs out of this the star will change again.

The length of the steady stade depends on the size of the star. Heavy stars transform their hydrogensources must faster into helium and other elements than light ones, because their internal pressure and temperatures are much higher. Therefor the nuclearenergy of the larger is faster depleted. They have a much shorter lifetime, about some tens of million years (a factor 10 shorter!) in stead of the ten billion years that smaller stars, like our sun, are alive.


Stars more or less of the size of our sun.
Smaller stars, about the size of our sun come rather peaceful to their end.

When all hydrogen is burnt, the gaspressure from the inside of the star and the gravity forces pressing from the outside get out balanced. The outer layers collaps and the star shrinks. This causes a rise in temperature inside the star and a new nuclear reaction starts.

The remaining helium starts to fuse to carbon, oxygen of neon. The energy generated from this reaction causes a expansion of the star. Because of its very large surface the outer layers cool down and emit red light. The star is now called a red giant.

As the star is very large it cools down rapidely, and now the star shrinks again. The shrinking makes the star more compact, the density increases, and so the inner parts are heating up again which causes new swelling. The luminosity of the stars will rise when the star shrinks and get less when it swell, the star now became a cepheid. During this proces lots of matter are swung into space under influence of the large quantities of energy that come from the nucleus, these are called sterreblizzards????.

When all helium is depleted, the inner layers do not have sufficient energy to remain swollen, so they collaps. The atoms are pressed together and get very densely packed. The mass of the star is more or less equal to that of our sun, while it collapses to a size of aproximately the Earth, so the star turns into a much smaller compact sphere. It now is a white dwarf, its mass is very dense, matter of a few grams on Earth weighs on a white dwarf several tonnes. It is mainly made out of carbonatoms, sometimes even in the cristalform of diamond, and it will slowly extinguish to a black dwarf. A black dwarf is not observed yet because it takes a very long time before the white dwarf is completely extinguished.

The larger stars.
The end of larger stars is much more sensational. After their much shorter lifetime, these become red supergiants. They sometimes reach diameters of over 1000 times that of our sun.
A planetary nebula
A supergiant contains many different elements, that are created by nuclearreactions. Here also the starblizzards??? peel off the cooler outer layers of the star. These expand into space and are known as planetary nebula. From this material full of more complex atoms and molecules planets may be formed around a second generation star.

The star remains as a smaller object that emits blue light, because of its high temperature. The red giant turned into a blue one. When finally iron is formed, the star comes to its end. Most large stars end their red or blue giant phase with an enormous explosion and go supernova, after which it finally is transformed into a neutronstar or, in case it was a super massive star, it turns into a black hole.


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