Type ll supernovas

what determines where a star will be on the main sequence?

mass will determine how long a star will live

what happens when a massive star tries to burn iron?

iron doesn’t produce energy so burning it will suck energy instead which will trigger the collapse of the star and cause it to explode into a supernova

how long will a star of 20 solar masses last?

it will burn hydrogen for 10 million years, helium for 1 million years, carbon for about 10k years, oxygen for a year, but its iron core will only last a day

why does it only go up to iron?

by fusion, its impossible to produce energy by fusing light elements into heavier elements, after iron the fusion absorbs energy instead of releasing - no more fusion can take place after iron

What triggers a Type-II supernova, and what reaction occurs during the star's core collapse?

the inward pressure due to the high mass of the star so there isn’t anything from stopping the star from collapsing - it does in a giant implosion, as it continues to becoming denser the protons and electrons react to become neutrons - as the collapse goes on the neutrons compress until they explode in a type-ll supernova

what happens to the outer envelope after a supernova?

it explodes and the core collapses into a neutron star or a black hole

what is a progenitor star?

A progenitor star is the original star that eventually evolves into a stellar remnant or explodes as a supernova.

• For a white dwarf, the progenitor is a low- to medium-mass star like the Sun.

• For a supernova, the progenitor is usually a massive star (more than 8 times the mass of the Sun).

how many stable and radioactive elements are there?

81 stable and 10 radioactive

what can a deadly supernova be?

a supernova that occurs at 50 to 100 lys or less can have deadly consequences such as destroying the ozone layer which can cause mass extinction

how can these elements be formed?

through successive alpha-particle fusion that are more abundant than those created by other fusion reactions - the last nucleus is nickle-56 which decays to cobalt-56 and then to iron-56 which doesn’t fuse or decay

how are elements beyond iron formed in the supernova?

there are a lot of neutrons available to interact with iron and other nuclei, since neutrons have no charge they can combine with positively charged nucleus more easily

what is neutron capture?

it can create heavier elements by allowing neutrons to interact with iron and other nucleui

what happens during the first 15 minutes of the supernova blast?

the number of free neutrons increases that will create the rest of heavy elements

what do shock waves do?

they can be the trigger needed to start the collapse process in an interstellar cloud, dying stars cause a shock wave which triggers the collapse of nearby gas and formation of new stars

what is the cycle of star formation?

they form, evolve, and die, when they die they send heavy elements into the interstellar medium and these elements become parts of new stars

what do we call something that has a sharp beam and spins like a light house?

a pulsar which is supported by neutron-degeneracy pressure and is known for its strong magnetic field and is about 10km

what type of supernova has a spectral analysis that shows its poor with hydrogen?

only type-l

out of stars with a mass of 2.2SM and 15.2SM which becomes a star faster?

the star with the mass of 15.2 SM

what is the min temp needed to trigger the helium to carbon reaction?

At least 100 million K.

what is the layer of H → He? what phase of its life is the star and what is the min temp it needed?

its called the hydrogen burning shell, its in its red giant phase and needs 600 million degrees to start fusion

what type of pressure supports white dwarfs against gravity? what is the max mass a WD can have? what is the limit?

electron pressure, it needs 1.4 solar masses, and the max mass is the chandrasekhar mass limit

what is the star that gets shiny suddenly and how much does its luminosity increase?

its a nova and its luminosity increases 10k times

what supernova is called a carbon detonation?

type-l

what element fuses last before the core collapses? what happens when the atoms collapse and what do they turn into?

it fuses iron turning into neutrons and exploding into type-ll supernovas

if a core has less than 3 masses it turns into what and if it has more?

if it has less it will turn into a neutron star and if it has more it will turn into a black hole

what type of supernova reaches iron core with elements burning around it with onion structure that leads to a supernova?

type-ll only