LA 175 OL1

1. The Orion Nebula
Birthing grounds of stars and
planets

2. Fact’s on the Orion Nebula
• Name: Orion Nebula, M42, NGC
1976
• Description: An emission nebula in
which stars are forming
• Age: Some stars in the nebula are
thought to be about 1 million years
old.
• Location: The Orion Nebula is
found in the sword of the
constellation Orion.
• Distance from Earth: 1,500 light-

3. Constelation
Orion
Orion is the 26th constellation in size,
occupying an area of 594 square
degrees.
It is located in the first quadrant of the
northern hemisphere (NQ1) and can
be seen at latitudes between +85° and
-75°.
The neighboring constellations are
Eridanus, Gemini, Lepus, Monoceros
and Taurus.
Orion contains three Messier objects –
Messier 42 (M42, NGC 1976, Orion
Nebula), Messier 43 (M43, NGC 1982,
De Mairan’s Nebula), and Messier 78
(M78, NGC 2068) – and has seven stars
with known planets.

4. Journey through the Orion
Nebula

5. At the end of the journey we noticed a
star was being born.
Since the Orion Nebula is the birthing
grounds for stars lets look closer at how
a star is born.
First we need to start at the beginning
with what components are need to
make a star.
Star Birth

6. Dust, Gas and Much More!
The first step in the birth
of a star is to wait. Dust,
gas, and other materials
sit around in nebulae,
and wait for eons until a
passing star, shockwave,
or other gravitational
disturbance passes
through or by the
nebula.
Top Image: in this image
we see all the different
gases and chemicals we
have identified so far in
the Orion Nebula.
Bottom Image: In this
image we see the ripples

7. This process is called accretion, and causes the stars to grow larger.
However, the molecules in the nebula have energy of their own, which resist this collapse. The cloud will only
collapse if its mass is large enough to allow this - a mass called the "Jean's Mass." This is derived from the
Virial Theorem (left). Rearranging this, and substituting in the equations for kinetic an potential energy, the
equation becomes:
Now, the number of particles in the cloud is equal to the mass of the cloud divided by the mass of the particles,
N=M/m, and assuming that the cloud has a constant density, you can relate its size to its mass by the equation
to the right. Rearranging, combining, and simplifying, we get the equation for Jean's Mass, MJ:
Accertion, Energy and Mass
If the cloud's mass is larger than this critical mass, then it will collapse. Otherwise, it will continue to swirl
and clump, but the clumps will not be permanent, and they will dissolve in the cloud.

8. Simple Review
So let’s simplify what we have learned so far. If you think
about how you make bread you have wet ingredients and
dry ingredients.
The wet ingredients are already together they mix well
together and not much happens. When you start to add
the dry ingredients a process starts and you start to get
dough.
To little and it wont make bread to much and you will get
something like a rock. When the right amount is added
and we apply heat we get bread.
Just like when gravity shrinks the gas it heats up and
nuclear reactions occur creating a star.

9. Protostar
Continuing on the road of accretion, assuming that the cloud's mass is above
the Jean's Mass, the clumps of matter continue to group together in the
nebula until they are gigantic clumps of dust and gas. By this time, the clumps
have reached sun-like sizes, and by that stage, the gas is dense enough that it
no longer loses heat to the surrounding nebula. It has become "adiabatically
opaque," and the heat that it generates is retained, and it starts to heat up. At
this stage, the clump is called a protostar. From the start of the collapse to
this stage, typical time scales are on the order of a few hundred thousand
years.

10. Protostars - Pre-Main Sequence
As the protostar becomes larger, gravity squeezes it tighter, causing
pressure to build and for the heat to increase.
On the Hertzsprung-Russell Diagram, the large swath of stars through
the center is called the "Main Sequence," and it is where most stars
live most of their lives. There is a period of time between when
protostars are formed and they reach the main sequence, and this is
called the "pre-main sequence."
The pre-main sequence to the right shows theoretical temperature vs.
luminosity of the protostars for several different masses. Low mass
stars contract and drop in luminosity until the interior opacity drops
and the energy comes flooding out, resulting in an increase in surface
temperature and luminosity. High mass stars have low opacity to begin
with due to high temperatures, and simply heat up as the contract.
Then, when the pressure in the center causes the core to reach a
temperature of 10,000,000 K (18,000,000 °F), hydrogen fusion is
initiated. Now, the protostar has become a star. It shines with its own
light. Its solar wind quickly pushes away the rest of the dust and gas in
its vicinity.
NOTE: A protostar that does not become hot enough to begin fusion, yet is no longer surrounded by its parent nebula is called a brown dwarf. A brown
dwarf usually has between 1/12 and 1/100 of the Sun's mass. It can still produce heat by contracting very slowly (i.e. decreasing its equatorial diameter
by a few millimeters a year), yet does not shine as a star does. Jupiter produces heat in this way, although it is too small to be considered a brown
dwarf. Most brown dwarfs have an average surface temperature of 1,800 K (2,700° F). There are an estimated one trillion brown dwarfs in our galaxy
alone, and some think they may be a source of the universe's missing mass.

11. A look at some Stellar Births!

12. Back inside the Nebula
As star’s are born inside the Orion Nebula the Nebula itself has
some fascinating thing’s going on.
The Orion Nebula has four monstrously massive stars,
collectively called the Trapezium.

13. Trapezium
The Trapezium, or Orion Trapezium Cluster, is a tight open
cluster of stars in the heart of the Orion Nebula, in the
constellation of Orion. It was discovered by Galileo Galilei. On
February 4, 1617 he sketched three of the stars (A, C, D), but
missed the surrounding nebulosity.
The fourth component (B) was identified by several observers
in 1673, and several more components were discovered later,
for a total of eight by 1888. Subsequently several of the stars
were determined to be binaries. Telescopes of amateur
astronomers from about 5 inch aperture can resolve six stars
under good seeing conditions.

14. Closer look at the
Orion Trapezium
Cluster

15. Orion Nebula’s Black Hole?
In 2012 Scientists say they may have found a
Black Hole of 200 solar masses in the heart
of the Orion Trapezium Cluster.
According to astrophysicists, including Dr.
Holger Baumgardt, the aforementioned force
is likely to be a Black Hole located
somewhere in the between the four bright-
shining stars that make up the famed Orion's
Sword, known in astronomy as the
Trapezium at the very core of the Nebula.

16. Black Hole?- Continued
The Black Hole is measured to be about 200 times as massive as our own sun reports
Cornell University Library. In astronomical terms, Orion sits in our "own backyard" a
mere 1000 or so light years away says Science 2.0.
Setting up a virtual computer model of the Orion Nebula, "representing a tight cloud
of inter-stellar gas containing the right combination of heavy and light stars."
Scientists then calculated the stars' movement within the confines of the system.
As gas kept being pushed outward, the calculations explained, thus causing the cluster
to expand and the stars to move around more rapidly. Dr. Baumgardt stated that
studying and crunching the numbers for such a dense cluster was a challenge as the
required computations were many.
Several of the heavy-massed stars were "sling-shot" from the cluster, where as others
were forced into the middle of it and collided with the most massive star within it.
Ultimately, said star became too massive, as well as unstable, and thus, collapsed into
itself becoming a Black Hole.
The research team also pointed out how the findings dramatically impacted their
perceptions on the formation of massive stars and how such rich clusters "hatch from
their gaseous cocoons."

17. What is a Black Hole?
A black hole is a place in space where gravity pulls so
much that even light can not get out. The gravity is so
strong because matter has been squeezed into a tiny
space. This can happen when a star is dying.
Because no light can get out, people can't see black
holes. They are invisible. Space telescopes with special
tools can help find black holes. The special tools can
see how stars that are very close to black holes act
differently than other stars.

18. Fun Video on Black Holes!
• 25 crazy facts about Black Holes that make
them not so scary.

19. Recap on the Amazing
Orion Nebula
• It is one of the brightest nebulae, and is visible to the naked
eye in the night sky.
• A nebula is an interstellar cloud of dust, hydrogen, helium and
otherionized gases.
• The nebula is thought to have a black hole at it’s center.
• Astronomers have directly observed protoplanetary disks,
brown dwarfs, and so much more inside the nebula.
• It has been noted in history since 1610 and is also thought to
have been depicted in Mayan culture.
• Since the Orion Nebula is visible to the naked eye it has been
one of the most popular Nebula’s in history and is the most
sought after.

20. Orion Nebula, M42, NGC
1976

21. Orion Nebula, M42, NGC
1976