Stellar Evolution: The Life and Death of Stars

Stars ,by definition, are astronomical objects consisting of luminous spheroids of plasma held together by their own gravity; they store most of the baryonic matter that forms galaxies.
There are two main physical levels that govern the dynamical behaviour of stars, both on the macroscopic and microscopic levels.Curious to learn more about the dynamics of stellar evolution? Keep Watching!!

Check it out: Stellar Classification: Types Of Stars!
https://youtu.be/ab_5MNP2OfQ
---
Subscribe for more videos:https://www.youtube.com/c/InsaneCuriosity?sub_confirmation=1?
Business Enquiries: Lorenzovareseaziendale@gmail.com
--
Star Formation

Stars form inside what’s known as molecular clouds, they are relatively dense regions of interstellar gas and dust with extremely cold temperatures at which the interstellar gas becomes of molecular form, in other words, the gaseous atoms bind together to form molecules and that’s why these clouds are referred to as molecular clouds. The most common molecules inside these clouds are carbon monoxide and hydrogen, and the extreme cold temperatures make the gas molecules form clusters of high densities, the star forms eventually when these densities reach a certain limit. The density of these regions makes them opaque to visible light and that’s why they’re called dark nebula; in order to observe or investigate them, astronomers use infrared and radio telescopes.
The beginning of the star formation happens when the denser parts of the dark nebula core collapse under the effect of their own gravity. The masses of these cores reach approximately (10 to the power 4) solar masses and they are mainly in the form of gas and dust. Bearing in mind that the core of the dark nebula is more dense than the outer cloud itself, it’s obvious that the cores collapse first. As the inner cores collapse under the effect of their own gravity, they disintegrate into clusters that are approximately 0.1 parsecs in diameter and (from 10 to 50) solar masses. Afterwards, the clusters form protostars in a process that takes around ten million years.
You may ask yourself, how do astronomers know these facts if the star’s birth takes place in the center of a dark nebula which is opaque to visible light? And the answer simply is, most of the dark nebula cores have infrared sources which constitute evidence of energy released from protostars collisions. Moreover, young stars are usually discovered with clouds of gas surrounding them, which are the dark nebula leftovers.

Protostars

Once a dust cluster has freely disintegrated from the dark nebula core, it becomes a gravitationally bound body with its unique gravity and characteristics and it’s called a protostar. Loose gas falls into the center of the protostar during its formation, kinetic energy is released in a form of heat by this infalling gas; causing the temperature and pressure of the protostar center to go up. At a certain point, when the central temperature reaches thousands of degrees, the protostar becomes an infrared source of energy. With the help of the Hubble Space Telescope, there are several candidate protostars that have been discovered in the Orion Nebula.
Within the initial collapse of the dust cluster, the cluster is transparent and the time interval of the collapse is relatively short. However, as the cluster adequates its own gravity, it becomes more dense and thereby more opaque to several types of radiation. One of which is the infrared radiation trapped inside the dense cluster and increasing the temperature and pressure of the core. At some point, the internal pressure stops the loose gas from falling into the center of the core. Therefore, the protostar becomes more stable as the dynamical equilibrium between the internal pressure and the infalling gas is achieved. The protostar has only about 1% of the total mass of the main sequence star, however, the star’s envelope keeps growing from the infalling material which is easily accreted because of the angular momentum of the protostar that turns it from an irregular shape to a rotating disk.

-------------------------------------------------------------------------------------------
"If You happen to see any content that is yours, and we didn't give credit in the right manner please let us know at: Lorenzovareseaziendale@gmail.com and we will correct it immediately"

"Some of our visual content is under a Attribution-ShareAlike license. (https://creativecommons.org/licenses/) in it’s different versions such as 1.0, 2.0, 3,0 and 4.0 – permitting comercial sharing with attribution given in each picture accordingly in the video."

Credits: Ron Miller
Credits: Nasa/Shutterstock/Storyblocks/Elon Musk/SpaceX/Esa
Credits: Flickr

Video Chapters:
00:00 Introduction
01:23 Star Formation
03:27 Protostars
07:02 Fate of Stars

#insanecuriosity #stellarevolution #stellar

Видео Stellar Evolution: The Life and Death of Stars канала Insane Curiosity