Mike Chris The Life Cycle of Stars
Dec 23, 2015
Mike
Chris
The Life Cycle of Stars
Life of a Small to Medium-Mass Star
Stars begin as a nebula, or clouds scattered dust made mostly of hydrogen
As the nebula collapses the contents of it begin to to heat up. This is known as a protostar
This phase can be referred to as the fetus of the star
Nebulas And Protostars
http://www.godandscience.org/images/nebula.jpg
Brown dwarfs are objects in space
They are not technically stars, and are bigger than planets
Brown Dwarf
http://seanf.hypexr.org/project/Brown_Dwarf.jpg
Brown Dwarf
The main sequence is where stars live most of their lives
Right now, our sun is in the main sequence
A star begins the main sequence when nuclear fusion begins
Main Sequence
http://www.noaanews.noaa.gov/stories2005/images/sun-soho011905-1919z.jpg
Main Sequence Star
Fusion
Nuclear fusion is
when two atoms
combine to make a
larger one
In stars this is
between hydrogen
and helium
When a star runs out
of hydrogen, it starts
fusing helium and
carbon
Larger stars can
fuse carbon into
even heavier
elements like iron
When a star starts burning helium, it starts to pack the atoms tighter together, causing the outside of the star to expand
When this happens, it is classified as a red giant
This is the first step into old age
Red Giants
http://www.lancs.ac.uk/ug/hilditch/pic3.gif
Red Giant
Planetary nebula is a nebula that has gas and plasma
Planetary nebulas are made of dead starsAfter a red giant a planetary nebula is made
Planetary Nebula
http://en.wikipedia.org/wiki/File:NGC6543.jpg
Planetary Nebula
The cores of low-mass stars are white dwarfsWhite dwarfs are close to the size of the Earth,
but may weigh as much as our sunThey are not as bright as larger starsWhite dwarfs are very bright because of the heat
made when the star collapsedA black dwarf is made when white dwarf
becomes coldBlack have not been proven to exist because
it takes longer for a white dwarf to become one than the universe has been in existence
White and Black Dwarfs
http://cactus.dixie.edu/smblack/chem1010/images/Unit_4/4A_white_dwarf_star.jpg
White Dwarf
Life of a High-Mass Star
Massive main sequence stars are the same as small or medium-mass except that they are bigger so they burn hydrogen faster
Massive Main Sequence
https://segue.atlas.uiuc.edu/uploads/ryemm2/blue%20main%20sequence.jpg
Massive Main Sequence Star
Supergiants are the largest stars in our universe
They can have a diameter of around 1,000 times bigger than our sun
Supergiant
http://isc.astro.cornell.edu/~sloan/fun/figures/star_agb.gif
Supergiant
A supernova is an explosion of a high-mass stars
This happens when a star’s supply of energy and light runs out
This only happens every few millions of years
Supernova
http://imagine.gsfc.nasa.gov/Images/bios/stecker/large.supernova.jpg
Supernova Remnant E0102-72
Neutron Star
A neutron star is
the result of a
supernova
A neutron star is
small and dense
and is mostly
made up of
neutrons , hence
the name
A neutron star is
bigger in mass
than our sun
http://nrumiano.free.fr/Images/Neutron_star_E.gif
Black Holes
A black hole is
another result of a
supernova
It is a thing in space
that has such a
strong pull of gravity
so strongly that light
can’t be seen
Until recently,
astronomers didn’t
know that black
holes even existed
because black holes
can’t be seen with a
telescope
http://ucsdnews.ucsd.edu/graphics/images/2006/neutron-star-jet_bg.jpg
Black Hole
Why high-mass and low-mass stars live different livesHigh-mass and low-mass
stars take different paths at the end of their lives
High mass stars burn their fuel faster than low-mass stars, which is why low-mass star live much longer than high-mass stars
Also, high mass stars end their lives with a supernova, then a black hole or a neutron star
Low mass stars end their lives by becoming a white dwarf
http://www.geosociety.org/graphics/04denver/blackhole.jpg
Black Hole
Ages of Different Mass Stars
Most
massive-20
million years
Our sun-10
billion years
Least
massive-1
trillion years
http://www.keyway2.ca/jpg/stars.jpg
http://nasascience.nasa.gov/astrophysics/how-do-stars-form-and-evolve
http://sunshine.chpc.utah.edu/labs/star_life/starlife_main.html
http://simple.wikipedia.org/wiki/Supergiant http://simple.wikipedia.org/wiki/White_dwarf http://simple.wikipedia.org/wiki/Red_giant http://simple.wikipedia.org/wiki/Black_hole http://simple.wikipedia.org/wiki/Main_sequence http://simple.wikipedia.org/wiki/Neutron_star
Sites