Module 2 Lesson 2 Flashcards
what is and hr diagram?
HR diagrams combine information about temperature, colour, size and luminosity.
Compare and contrast absolute magnitude and apparent magnitude, luminosity, spectrum.
differences:
Luminosity- total amount of energy a star radiates per second.
apparent magnitude- the brightness of a star as it APPEARS to us
Absolute magnitude- the ACTUAL amount of light given off by a star at a standard distance
Light spectrum is the many different wavelengths of energy produced by a light source. (eg: star)
similarties:
all of this releates to light
Describe how stars evolve and what happens when they die
stars evolve due to fusion. the star collapses when the gravity exceeds pressure, the star expands when pressure overcomes gravity. this causes the stars to evolve.
low mass stars become white dwarfs then black dwarfs when they die
intermediate mass stars become red giants, white dwarfs then black dwarfs when they die
high mass stars become supernova and then either a black hole or a neutron star
what is a super nova. how and when does a super nova occur?
it is the explosion of a star.
When the pressure drops low enough in a massive star, gravity suddenly takes over and the star collapses
what is a red dwarf
a red dwarf is the smallest and coolest star on the main sequence
what is a black hole? when and how does it occur?
A black hole is a place in space where gravity pulls so much that even light can not get out.
A black hole can be formed by the death of a massive star.
When such a star has exhausted its fuels in its core. the core becomes unstable and gravitationally collapses inward upon itself which forms a black hole
what is a white dwarf
A white dwarf is what stars become after they have exhausted their nuclear fuel
what is a nebula
A nebula is an enormous cloud of dust and gas. (it is what creates new stars)
what is a planetary nebula
it sheds its outer layers, which form a beautiful cloud called a “planetary nebula”, while the dying star’s core becomes a white dwarf.
(large stars a planetary nebula when dying not small stars)
what is a main sequence star
Main sequence stars are stars that are fusing hydrogen atoms to form helium atoms in their cores.
How do the stars’ luminosity compare with their radii?
stars with a larger radius have a higher luminosity
how does a stars radii compare with their mass?
as the radius increases the mass increases
Why would the size of a star affect its luminosity?
As the size of a star increases, luminosity increases. If you think about it, a larger star has more surface area. That increased surface area allows more light and energy to be given off.
what are the different star groups?
white dwarfs, main sequence, supergiants and giants
what is the temperature of a blue and red star
blue stars are hotter
red stars are cooler
look at hr diagram
look at hr diagram
why do some stars appear brighter and others do not?
stars may appear brighter because they may be closer to earth or they may be larger
what is luminosity
Luminosity- total amount of energy a star radiates per second.
what is apparent magnitude?
Apparent magnitude- the brightness of a star as it APPEARS to us
what is absolute magnitude?
Absolute magnitude- the ACTUAL amount of light given off by a star at a standard distance
Eg. If all stars were the same distance from earth, the sun would not be brightest.
explain the life cycle of a small to medium star
there are clouds of dust and gas and if it is big enough its own gravity will start to collapes so it folds in on itself toward the center of the cloud which causes the center of the cloud to become denser, hotter. eventually the particles of the gas and dust are made of are brought close to each other which causes them to fuse.
inside every newborn star hydrogen atoms fuse together to make a helium. the process is known as (fusion). fusion creates the energy for every star
the main sequence is red dwarf.
at some point hydrogen runs out. the core of the star will start to collapes on its self under its own weight. which leads to only the star to be left with its core. which is called a white dwarf
white dwarf will cool down to become a black dwarf
birth and early life: protostar and nebula
main sequence: red dwarf
old age: white dwarf
death: black dwarf
remains: black dwarf
explain the life cycle of a large star
there are clouds of dust and gas and if it is big enough its own gravity will start to collapes so it folds in on itself toward the center of the cloud which causes the center of the cloud to become denser, hotter. eventually the particles of the gas and dust are made of are brought close to each other which causes them to fuse.
inside every newborn star hydrogen atoms fuse together to make a helium. the process is known as (fusion). fusion creates the energy for every star.
for the main sequence of a large star it becomes yellow/orange
at some point hydrogen runs out. the core of the star will start to collapes on its self under its own weight and becomes more denser and hotter
when stars fuse helium it creates more eneergy. that causes the outer layers of the star to expand. the sun will grow so large it will become a red giant. soon the outer layers will drift away which forms a planetary nebula
this cauuses the star to be left with only its core which is called the white dwarf.
white dwarf will cool down to become a black dwarf
birth and early life: protostar and nebula
main sequence: yellow/orange stars.
old age: red giant
death: white dwarf
remains: black dwarf
explain the life cycle of a giant star
there are clouds of dust and gas and if it is big enough its own gravity will start to collapes so it folds in on itself toward the center of the cloud which causes the center of the cloud to become denser, hotter. eventually the particles of the gas and dust are made of are brought close to each other which causes them to fuse.
inside every newborn star hydrogen atoms fuse together to make a helium. the process is known as (fusion). fusion creates the energy for every star.
the main sequence of a giant star is blue.
then because the star is so big it is able to fuse heavier elements inside its core. once it reaches its limite the core starts to collapse. this creates the super giant which then leads to a huge shock wave which causes a super nova explosion.
after the star becomes either a balck hole or a neutron star
birth and early life: protostar and nebula
main sequence: blue stars, big, hot and bright
old age: super giant
death: super nova
remains: black hole or neutron star
REMINDER: measurements
temperature is measured in K.
Luminosity is measured in suns
radius is measured in suns
