Rubin Planetarium Video - Supernovae
A supernova is an explosion that occurs upon the death of certain types of stars. There are two known causes of supernovae. In the first instance, called a “Type Ia” supernova, a white dwarf collapses and explodes after accreting enough mass to exceed the Chandrasekar limit. In this case the star is completely destroyed. Because the white dwarf is always the same mass, Type Ia supernovae can be used as standard candles to measure the distances to their host galaxies. The second kind of supernova is a “core-collapse supernova,” which occurs when the core of a massive star collapses and explodes. Much of the mass of the star is ejected into space at a high velocity while the core collapses into a neutron star or black hole. In both cases the shockwave produced by a supernova can trigger the formation of new stars.
Supernovae are incredibly bright. For several months after the explosion, a supernova can be as luminous as the rest of the stars in its galaxy. For this reason supernovae can be seen in galaxies that are billions of light years away. Supernovae are relatively rare; in a galaxy the size of the Milky Way, supernovae explode roughly two or three times a century.
Astronomers have discovered roughly 50,000 supernovae. During the ten years of its survey, LSST will discover three to four million more. Roughly half of these will be Type 1a supernovae, which can be used to measure the distances to some of the most remote galaxies in the observable universe.
This animation depicts a “core collapse” supernova as seen from near the star, and then from an external view of the remnant.
The initial vantage point is from the outskirts of the star system, with the red giant star (itself as large as our inner solar system) seen as a small disk. It pulsates several times in brightness and temperature before the explosion.
The star explodes initially with a bright spike in light, fading to reveal a turbulent shell of ejecta sweeping past our vantage point. The faint glow of a neutron star remnant at the center of the explosion.
Our vantage point now pulls away to show the expanding remnant from an external view, connecting the original inside-the-shell view to what we see as astronomers observing it from the outside. Parallax in the foreground starfield establishes the size of the remnant as much larger than the original star system.
We have now stopped moving away from the explosion, and we begin rotating around it. Since we are now at a constant distance, the ongoing expansion of the irregular remnant can be seen through the end of the sequence.
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