The
star types in our galaxy are classified according to their brightness and their
elements. A star can be classified into specific categories, depending on its
temperature, color, distance and much more. So let's talk about how many types
of stars there are in our galaxy.
Have you ever wondered how many
types of star are in our galaxy? If not, it might be a good idea to get to know
the basics of astronomy now. If you're like most people, you probably simply
learned about the different types of stars in school as children. And that's
okay, but knowing which type of star comes through and when will help you
understand the different phases of your solar system and what happens inside
planets over time. Plus, if you want your kids to pick up some science skills
without having to dive into hard topics like quantum mechanics, this is an easy
way to learn while they're entertaining themselves.
Here are different types
of stars:
1. The Milky Way galaxy is home to 100
billion stars:
The Milky Way galaxy is home to
100 billion stars. The Sun is one of them, along with all the other stars in
the solar neighborhood, including our closest neighbor, Proxima Centauri.
The Milky Way galaxy is a
barred spiral galaxy with a diameter of about 1,000 light-years across. It is
one of the largest galaxies in the Local Group of galaxies, which includes our
own Milky Way and Andromeda galaxies.
It has several prominent spiral
arms winding out from its center that appear like rivers winding around an
island. The arms contain cool gas and dust that can be seen as dark streaks
running through otherwise bright stars.
There are two main components
to this image: The first image shows a composite of visible light from
individual images taken by Hubble's Advanced Camera for Surveys in March 2003
through August 2012 (top) and infrared data from NASA's Spitzer Space Telescope
(bottom).
2. Our galaxy is 100,000 light years in
diameter:
Our galaxy is 100,000 light
years in diameter and contains about 200 billion stars.
The most common type of star is
the yellow dwarf. This type of star gives off only 100,000 times as much light
as our Sun does, but it has a mass of about 10 times that of our Sun and lives
for tens to hundreds of billions of years. The next most common type is the red
dwarf star, which is smaller than the yellow dwarf and has a mass about 20
times that of the Sun. Red dwarfs live for only tens to hundreds of millions of
years before they become cool enough to undergo nuclear fusion reactions in
their cores. The final type is the white dwarf, which is smaller than the red
dwarf and has a mass equal to that of Jupiter or Saturn combined—about 1/10th
that of the Sun. White dwarfs last for only a few thousand years at most before
they cool down enough to no longer glow by hydrogen fusion reactions in their
cores.
3. Nuclear fusion powers stars:
Stars are fueled by nuclear
fusion. This process occurs when atoms of hydrogen fuse together to form helium
atoms. The energy released during this process is so great that it causes the
star to shine brightly.
Stars vary in size and type,
but all stars have a core of hydrogen and helium which produces energy through
nuclear fusion (bio-nuclear fusion).
The Sun, our nearest star, has
a diameter of 864,000 km at its equator (or 1/12th the diameter of the Earth),
giving it an estimated mass of 1.90 x 10**27 kg or about 2x10**24 Joules
(energy). The Sun's gravity pulls matter from deep within itself towards its
surface through a process called convection at a rate of about 3x10**9 kg/s
into a vast volume known as the Solar System. It takes approximately 200
million years for this material to reach the surface and only then do we see it
as asteroids and comets orbiting it.
4. Most stars are red dwarfs:
Our galaxy contains about 100
billion stars, and there are about 200 billion galaxies in the observable
universe. So, at least one in every 10 stars is a red dwarf.
Red dwarfs are less than half
as massive as the sun, but they’re still huge by star standards. They’re also
much cooler than our Sun — only about 2700 degrees Fahrenheit (1550 degrees
Celsius) on average.
Because of their dimness and
coolness, red dwarfs aren’t usually seen by humans. They’re so faint that they
might not register as a star in optical telescopes, even if they were visible
with the naked eye.
5. Red giants are the largest types of star:
Red giants are the largest
types of star. They are approximately 50 times larger than our sun and have
exhausted their hydrogen fuel. The star is expanding and creating a large red
giant with a surface temperature of over 10,000 degrees Fahrenheit.
The largest known red giant is
Betelgeuse, which is a red supergiant located in the constellation Orion. It
has an outer radius of over 1,900 solar diameters and an estimated mass of 1.5
million times that of our sun. It is about 700 light years away from us and it
will continue to grow for about another 1,000 years before it will become a
black dwarf.
6. White dwarfs make up 20% of stars in the
universe:
White dwarfs are the smallest
and densest stars, which make them the hottest. They are not as massive as main
sequence stars like our Sun, but they are still hot enough to radiate energy at
a much higher rate than cooler red dwarf stars.
White dwarfs make up 20% of
stars in the universe, although they’re rarer than other types of stars. The
highest concentration of white dwarfs is in globular clusters, where they can
form over time due to gravitational collapse.
White dwarfs are also
interesting because they’re not all the same size. Some white dwarfs, called
Population I objects (or P-I objects), have relatively low masses and
temperatures; others have high masses and temperatures. These differences may
be caused by different amounts of material or temperature at various distances
from their centers.
7. Blue giants are extremely rare:
Blue giants are extremely rare.
They are so rare, in fact, that scientists aren't exactly sure how they form.
Blue giants are thought to be the end result of a star that runs out of its
fuel supply and explodes as a supernova.
But even if this is true, it
still doesn't explain how blue giants avoid exploding. If a star has enough
fuel in its core to explode as a supernova, then it should have enough fuel to
become a blue giant instead.
So what's going on?
One theory suggests that blue
giants aren't really blue at all — they're actually red giants with a very
bright surface layer. The surface layer absorbs more light than expected from
its surroundings, which makes it look bluer than normal stars do.
8.Neutron stars are the smallest, densest
types of star:
Neutron stars are the smallest,
densest types of star. They have a radius of about one kilometer and weigh as
much as our Sun.
Neutron stars are born when
massive stars end their lives with a supernova explosion. A neutron star is
formed when most of the mass in the original star collapses into a very small
area, leaving behind only its core.
When you look at a picture of a
neutron star, you'll see it is so dense that it looks like pure matter, even
though it has no color or texture to it. This makes them difficult to see from
Earth because they are extremely dim and faint compared to other celestial
objects.
9. Black holes can form from neutron stars
or white dwarfs:
Black holes can form from
neutron stars or white dwarfs.
Neutron stars are formed when a
star dies in a supernova explosion. As the star collapses, it becomes very
dense and hot, forming a superdense neutron star with about 1.4 times the mass
of our Sun squeezed into an area no bigger than Manhattan.
White dwarfs are the end result
of low-mass stars that have already burned out, but have not yet collapsed into
black holes. When they get too close to their death throes, they will explode
as supernovae and collapse into even denser objects known as neutron stars or
black holes.
Conclusion:
Stars represent the fundamental
building blocks of the universe. We know a great deal about them, and there are
a variety of fascinating facts about these cosmic objects. But what we don't
know is even more astounding than what we do know. As far as we can tell from
observing the universe, stars have always been around, but the universe has
existed for only 13.8 billion years (that's an unbelievable fact in itself),
which means that it took almost 13 billion years for life to develop on Earth,
and 2 billion years after that for us humans to evolve. That's incredible
beyond words.
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