2006-12-27 21:33:01 · 5 answers · asked by lolman180 3 in Science & Mathematics ➔ Astronomy & Space
Type I Novae are a subset of all supernovae. Roughly speaking, supernovae are classified by looking at the spectral lines in the light they emit when they are at their peak brightness. If there is evidence for hydrogen in the spectrum they are called "Type II", if not they are "Type I."
Within the Type I class they are further subdivided by what other elements are present. For example, if their is evidence for silicon in the spectral pattern then the novae is classified as Type IA, and so on.
The type IA supernovae are special in that they are very well understood theoretically. They are believed to be the result of the explosion of a carbon-oxygen white dwarf star. The computer models that theorists have used to understand the duration of the explosion and the spectral lines are very good at reproducing the data for this class of novae. Since they are so accurate in these details, it is reasonable to assume that the models are also predicting the correct absolute intensity of the light as well.
That's important for the following reason. If you look up into the night sky you see a lot of stars. How do you tell which ones are far away and which are close by? You might think the bright ones must be closer than the dim ones, and that would be a good assumption if all stars were equally bright (say as bright as the sun). But of course, they're not equally bright.
But we believe all type IA supernovae are equally bright, at least to a reasonable degree of accuracy. Hence, the name "standard candles" is used to refer to these objects. So when we see a supernova with the characteristic spectrum of a type IA nova then we can look at its apparent brightness to gauge its absolute distance. And this lets us study how certain cosmological features may change with time, since the more distant an object is the farther back in time when its light was emitted to reach us now.
2006-12-27 22:54:20 · answer #1 · answered by . 5 · 1⤊ 2⤋
A nova (pl. novae) is a cataclysmic nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star.
A supernova (pl. supernovae) is a stellar explosion which produces an extremely bright object made of plasma that declines to invisibility over weeks or months. A supernova briefly outshines its entire host galaxy. It would take 10 billion years for the Sun to produce the energy output of an ordinary Type II supernova.[1] Stars beneath the Chandrasekhar limit, such as the Sun, are too light to ever become supernovae and will evolve into white dwarfs.
There are several different types of supernovae and two possible routes to their formation. A massive star may cease to generate fusion energy from fusing the nuclei of atoms in its core, and collapse under the force of its own gravity to form a neutron star or black hole. Alternatively, a white dwarf star may accumulate material from a companion star until it nears its Chandrasekhar limit and undergoes runaway nuclear fusion in its interior, completely disrupting it. This second type of supernova is distinct from a surface thermonuclear explosion on a white dwarf, which is called a nova. In either type of supernova, the resulting explosion expels much or all of the stellar material with great force.[2]
The explosion drives a blast wave into the surrounding space, forming a supernova remnant. One example of this process is the remnant of SN 1604, shown to the right.
"Nova" is Latin for "new", referring to what appears to be a very bright new star shining in the celestial sphere; the prefix "super" distinguishes this from an ordinary nova, which also involves a star increasing in brightness, though to a lesser extent and through a different mechanism.
2006-12-28 03:08:35 · answer #2 · answered by Anonymous · 2⤊ 1⤋
The middle of a megastar is powered by using the nuclear fusion of hydrogen atoms. they're being fused into the atoms of heavier factors (helium and previous). The middle of a planet is composed of the textile that the planet replaced into initially produced from, in a molten state through severe temperature. the warmth on the middle of a planet is especially through severe pressures, chemical reactions and the decay of radioactive factors. As planets age they're going to cool off and theoretically the interior will thoroughly solidify.
2016-12-11 17:29:44 · answer #3 · answered by sherburne 4 · 0⤊ 0⤋
A super nova is just one massive star collapsing and exploding at the end of it's life. A nova is two stars in close orbit around each other, with gas from one star escaping to the other star. The flare up occurs when the gas is compressed enough falling into the star to fuse and explode.
2006-12-27 21:50:00 · answer #4 · answered by Anonymous · 1⤊ 2⤋
A nova fuses accreted hydrogen near its surface.
A supernova fuses heavier elements, usually near its core.
A supernova is consequently a far more violent event.
2006-12-27 22:41:02 · answer #5 · answered by Anonymous · 2⤊ 1⤋