The Orion NebulaBirthing grounds of stars and

planets

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 yearsold.

• Location: The Orion Nebula isfound in the sword of the constellation Orion.

• Distance from Earth: 1,500 light-years

ConstelationOrion

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.

Journey through the Orion

Nebula

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

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 or disturbances that start

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.

Simple Review

So let’s simplify what we have learned so far. If you thinkabout 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 addthe dry ingredients a process starts and you start to get

dough. To little and it wont make bread to much and you will getsomething 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.

Protostar

Continuing on the road of accretion, assuming that the cloud's mass is abovethe Jean's Mass, the clumps of matter continue to group together in thenebula until they are gigantic clumps of dust and gas. By this time, the clumpshave reached sun-like sizes, and by that stage, the gas is dense enough that itno longer loses heat to the surrounding nebula. It has become "adiabaticallyopaque," and the heat that it generates is retained, and it starts to heat up. Atthis stage, the clump is called a protostar. From the start of the collapse tothis stage, typical time scales are on the order of a few hundred thousandyears.

Protostars - Pre-Main SequenceAs the protostar becomes larger, gravity squeezes it tighter, causingpressure to build and for the heat to increase.

On the Hertzsprung-Russell Diagram, the large swath of stars throughthe center is called the "Main Sequence," and it is where most starslive most of their lives. There is a period of time between whenprotostars are formed and they reach the main sequence, and this iscalled the "pre-main sequence."

The pre-main sequence to the right shows theoretical temperature vs.luminosity of the protostars for several different masses. Low massstars contract and drop in luminosity until the interior opacity dropsand the energy comes flooding out, resulting in an increase in surfacetemperature and luminosity. High mass stars have low opacity to beginwith due to high temperatures, and simply heat up as the contract.

Then, when the pressure in the center causes the core to reach atemperature of 10,000,000 K (18,000,000 °F), hydrogen fusion isinitiated. Now, the protostar has become a star. It shines with its ownlight. Its solar wind quickly pushes away the rest of the dust and gas inits 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.

A look at some Stellar Births!

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.

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.

Closer look at the

Orion Trapezium

Cluster

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.

Black Hole?- ContinuedThe 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."

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.

Fun Video on Black Holes!

• 25 crazy facts about Black Holes that make them not so scary.

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.

Orion Nebula, M42, NGC 1976

Orion Nebula, M42, NGC 1976