In the section below, we will discuss what is an accretion disk, where is accretion disk found, properties of accretion disk, importance of accretion disk.
What is an accretion disk?
An Accretion Disk is most often a circumstellar disk like structure. It is formed from a collapsing cloud of cosmic gas and dust. The word “accretion” denotes the movement and collection of additional material. Thus accretion disk is formed by the diffusion of material in orbital motion around any central body. The central body being mentioned can be any one of these
MUST READ: Facts about aurora borealis and australis
What is an accretion disk: Location
The places where these accretion disks are more likely to be found are in the binary star systems. The binary star systems comprise of two stars orbiting each other and the active galactic nuclei. The galactic nucleus for most of the known or explored galaxies is found to be a star. So we can also say that the central body is typically a star.
Now as we are discussing the astronomical bodies having immense masses, gravity always is at work. Here, Gravity causes material in the disc to spiral inward towards the central body.
What is an accretion disk: Properties
Gravitational forces compress the material to such a great extent that it causes the emission of various rays. These rays belong to various group of the electromagnetic spectrum. The frequency range of the radiated rays depends on the central body. The Accretion disc of young stars and proto stars both emit the infrared radiation. And those of the neutron stars and black holes radiate the x-ray part of the electromagnetic spectrum.
What is an accretion disk: Common Phenomenon
The Accretion disk is found to be quite common in the astronomical events. The astronomical events that include them are:
gamma ray bursts
the active galactic nuclei
proto planetary discs
Scientific observations indicate that the accretion disc often produce plasma jets. They do so through a mechanism whose impact on the formation of the central body and surrounding planetary system is not very well known. However, some theoretical models put forward by scientists suggest the magnetic field play a very crucial role in this process of radiation. Yet, no observational proof exists about these fields till now. But the research is in motion every time for their practical existence in this sphere.
What is an accretion disk: Deep study
Now, we would be going a little ahead for a bit deep study of the accretion disk. Let us take a binary star system, just for an example. The process is almost the same for any of the other case also. One of the star in the binary system is considered to be a compact object and other just a normal star.
We chose the compact object to be a very dense white dwarf star. The other star is just a normal star like the Sun. Now, the white dwarf can pull gas off the normal star and accrete it onto itself. Both the stars are revolving around each other. The angular momentum must be conserved.
MUST READ: THE REASON FOR CHANGE IN SEASONS
This gas cannot fall directly onto the white dwarf. Thus, it spirals in to the white dwarf. It gains energy for more proximity it gets each time. Thus, eventually, all the material flowing from the normal star to the white dwarf piles up in a dense spinning accretion disk orbiting the white dwarf. The gas in the disk becomes very hot due to friction. And gradually loses angular momentum and falls onto the white dwarf. Since this hot gas is being accelerated continuously, it radiates energy. This radiated energy falls in the x ray spectrum for the binary star system. And the astronomers detect it and use to identify and study the accretion disk.
What is an accretion disk: Their importance
The study of the accretion disk can be stated quite important. Their importance and the enthusiasm of the astronomers lies in the fact that none of the heavenly bodies in the universe have ever formed without them! That is to say that the accretion disk can be considered as the basic building block of the heavenly bodies.
What is an accretion disk: Your turn
Now, it is all up to you, the readers. Tell me whether the article was knowledgeable. Also, in case you have more information regarding the topic, you can add it. The comment section below is present for the purpose.