Hello and welcome everyone ,today we are going to discuss about cloud. Oh Wait ,I am not talking about the cloud which we see in sky. Here I am talking about interstellar cloud (A Cloud with accumulation of gases, plasma and dust). So basically in this Article: What are different types of nebula ? we will discuss about definition of nebula, different types of nebula and also how nebula are formed. So without wasting our time lets Start our discussion. So, we will start with definition of nebula.
What is the definition of a nebula ?
So, as we have discussed above that nebula is an Interstellar cloud. Now we will define it in a accurate way. So, basically nebula is an Interstellar cloud of Space dust or cosmic dust, hydrogen, helium and many other ionized gases.
So, this is all about the definitation of a nebula, now we will see some different types of question based on nebula and then We will discuss about different types of nebula.
Q. In general how much area is covered by a nebula ?
* If we talk about size of a nebula then, most of the nebula are of vast Size and also some of them are around hundreds of light years in diameter.
Q. Which is the brightest nebula in the Sky ?
* Orion Nebula is the brightest nebula in the Sky.
Q. Definition of Orion Nebula ?
* Orion nebula is a diffused type of nebula, which is situated in the milky way galaxy. And the interesting fact is that this nebula is visible to the nacked eye in the night sky.
Q. What is the another name of Orion nebula ?
* The another name of Orion nebula is Great nebula or the Great Orion nebula.
Q. What are different types of nebula?
* There are mainly four different types of nebula:
1) Diffuse nebula
2) Planetary nebula
3) Protoplanetary nebula
4) Supernova remnants
Q. What are different types of diffuse nebula ?
* There are three different types of diffuse nebula :
1) Emission nebula 2) Reflection nebula 3) Dark nebula
So, these are all important question related to nebula. Now lets talk about different types of nebula in detail.
Different types of nebula:
1) Diffuse nebula
2) Planetary nebula
3) Supernova remnants
4) Protoplanetary nebula
1) Definition of a Diffuse nebula:
Diffuse nebula is a type of nebula which do not have well defined boundaries. It means that their expansion is throughout the space but they do not have a specific boundary.
Now , lets talk about types of diffuse Nebula .
Diffuse nebula can be divided into :
1) Emission Nebula
2) Reflection Nebula
3) Dark Nebula
* Emission Nebula :
Emission nebula is visible light nebula , which means they emit spectral line radiation from ionized gases.
* Reflection Nebula :
Reflection nebula is a type of nebula which do not emit significant amount of visible light, But these types of nebula reflects the light with the help of star near them and thus they are visible.
*Dark Nebula :
Dark nebula is also a type of diffuse nebula , But this type of nebula neither emits the radiation nor reflects the light from them. Because they are not near a star. Now the question is If they are unable to reflect light and emit radiation , then how this type of nebula are detected ? , So this type of nebula can be detected as opaque clouds blocking the light from luminous objects.
2) Definition of a Planetary nebula :
Planetary nebula are type of nebula which are remnants of the stars with lower mass.
The definition of planetary nebula do not clearly explain the accurate characteristic of nebula , Now lets talk about how this planetary nebula is formed. So basically the formation of planetary nebula starts when a giant star expels its outer layer in the outer space , because of this expel , a gaseous shell is formed.
As we all know when a star die it becomes a white dwarf. So in this case , when a white dwarf is formed then , it excites the expelled gases and thus a emission nebula is formed. Which are similar to Planetary nebula and and after millions of year they completely becomes the planetary nebula with more dense and compact structure.
3) Supernova remnants :
As we all know a supernova occurs when a massive star dies. So , when a star die due to stoppage of nuclear fusion in the core of the star, then the star collapses. As the Star collapses it creates the strongly heated region and due to high pressure of heat the star explodes in the outer space. After this explosion a region of expanding gas shell forms this leads to the formation of a Supernova remnant nebula. So , In the simple words we can define a Supernova remnants that it is a type of nebula formed from supernova explosion.
4) Definition of a Protoplanetary nebula :
In actual they are not a permanent nebula. It means that Protoplanetary nebula are astronomical objects , which comes in existence between giant star phase and planetary nebula phase. The phase of this Protoplanetary nebula continues until the temperature of the central star reaches 30,000k.
So this is all about different types of nebula now lets see How nebula is formed ?
How nebula is formed ? : Formation of Nebula :
As we all know there are different types of nebula , So obviously there will be different types of mechanism for the formation of a nebula.
Some of the mechanism based on formation of nebula are :
Some of the nebula form from the gases which are already in the Interstellar medium, while others are formed when a star goes supernova or when a star becomes white dwarf.
As we have studied in the above topics that how a planetary nebula formed and also how a emission nebula is formed. In general all the nebulae are formed with the same mechanism.
So, this is how a nebula is formed with the help of massive stars and supernova explosion.
What is the Orion nebula is made of ?
Orion nebula is made of a region of neutral hydrogen known as Photodissociation region ( Basically Photodissociation region is the neutral region of Interstellar medium).
About the Post :
So far we have learnt many things from Article : What are different types of nebula ? Like , What is the definition of a nebula , some important question related to nebula and most important , Different types of nebula and also we saw about Orion nebula.
I hope you enjoyed reading this Article: What are different types of nebula ? And thats it for today , enjoy reading other articles which are given below , have a good day.
Originally published at https://astroquantumphysics.com.