Table of Contents
What is the difference between a nova and a supernova?
A nova is an explosion from the surface of a white-dwarf star in a binary star system. A supernova is a violent stellar explosion that can shine as brightly as an entire galaxy of billions of normal stars.
How could supernovae type Ia be used as standard 4 candles?
Since type Ia supernovae have a known brightness they can be used as standard candles to determine the distance to a galaxy once the stretch-factor is accounted for. Using the light curves, determine the apparent magnitude of the supernova at its peak brightness and then find the distance to the galaxy.
Why does a type II supernova explode?
The collapse of the inner core is halted by neutron degeneracy, causing the implosion to rebound and bounce outward. The energy of this expanding shock wave is sufficient to disrupt the overlying stellar material and accelerate it to escape velocity, forming a supernova explosion.
What’s more powerful than a supernova?
A hypernova (sometimes called a collapsar) is a very energetic supernova thought to result from an extreme core-collapse scenario. It is a type of stellar explosion that ejects material with an unusually high kinetic energy, an order of magnitude higher than most supernovae, with a luminosity at least 10 times greater.
How much brighter is a supernova than a nova?
A nova is the result of “eruption of a very old dying star”(3); supernova is also the result of a dying star but it is the result of a “violent” explosion of the star (3). Meaning the amount of energy released in a supernova is much greater than that released in a nova; usually this value is about 1044 Joules (4).
What is the brightness of the Type 1 supernova?
A typical supernova reaches its maximum brightness about 20 days after explosion. At its brightest, a normal Type Ia supernova (SN Ia) reaches an absolute visual magnitude of −19.5 and has a luminosity exceeding 1043 erg/sec, billions of times that of the Sun.
Why do all white dwarf supernova have the same brightness?
Type Ia supernovae happen when a white dwarf, the “corpse” of a star similar to the Sun, absorbs material from a twin star until it reaches a critical mass—1.4 times that of the Sun—and explodes. Because of their origin, all these explosions share a very similar luminosity.
How does the brightness of a core collapse supernova change over time?
A light curve is a plot of how bright the supernova is over time. Type II supernovae (which are thought to be the result of core collapse of a massive star) generally have a plateau in brightness before dimming more slowly. Their peak brightness can last several months.
What is the difference between type I and II supernovae?
A type I supernova occurs in closed binary systems where two average stars orbit around each other quite closely. A type II supernova occurs in larger stars of around 10 solar masses. After it leaves the main sequence it starts fusing increasingly heavy elements in shells around the core.