Abstract
Stars are interesting components in the universe and although it is not easy for a layman to comprehend their existence, research carried out in this field has helped us know much about stars.
One of the discoveries is that a star undergoes a lifetime just like any other living organism (e.g., the human beings); stars are born, they undergo some processes while living or existing and they eventually die.
A star’s lifespan is however affected by various aspects the major determinant is its mass. Pressure, temperature, and gravity also play a role in the life span of the stars.
Introduction
Stellar evolution entails a progression (which involves some notable changes) through which a star undertakes in its entire lifetime. Stars have got varying lifetimes depending on their masses where the more massive the star, the lesser the lifetime and vice versa.
The study of stellar evolution is complicated since it is not easy to note the life of a particular star since the changes take place slowly hence necessitating the study of various stars at different stages in life at a go (Night Sky Observer 4). This essay looks into the process of stellar evolution and the factors that influence it.
The Star
Stars are believed to originate from molecular clouds as well as the dense clouds of gas. A star forms from a big cool mass of gas that arises from the collapse of the dense regions contained in the clouds (Delehanty 1).
There are usually some contractions of the gases that form the star with a successive increase in temperatures. The nuclear reaction then happens where hydrogen atoms and hydrogen deuterons combine to form helium generating a lot of energy and preventing any other contraction of the star.
The star is known as the main sequence star the moment it commences nuclear fusion.
The star reaches the end of its main sequence lifetime once it reaches a point where approximately half of its core fuel is exhausted and hence making it difficult for the star to carry on a hydrogen fusion reaction.
The death of a star is determined by its type and mass, for instance, when a less massive star exhausts its hydrogen supply, the heat to support its core against the force of gravity is no more leading to the collapse of the core to allow for the density that can support conversion of helium to carbon.
Massive stars, on the other hand, tend to burn brighter and die much more radically. The lower the mass of a star, the longer the time it will live and the less violent its death and the higher the mass of a star, the shorter it lives and the more violently it dies.
Some of the factors that influence the evolution of a particular star include the chemical composition in the cloud that forms the star and the quantity of the components in the cloud which undergoes condensation to form the specific star.
The temperature within the core of a star also determines its destiny. The mass of the star is, however, the most essential and influential factor that determines its lifetime especially when other factors are kept to a constant.
More massive stars are deemed to shine much brighter and to burn out the supply of nuclear energy in their core much faster as compared to the lighter stars. The larger a star is the more fuel it has to burn and the shorter the life spans and vice versa (Newman 11).
Conclusion
In a nutshell, a star goes through various stages in its entire lifetime highlighted as follows; the nebula which entails the clouds forming the star, the protostar, the main sequence, the actual life span, the giant and lastly old age (King 1).
Works Cited
Delehanty, Marc. “Stellar Evolution, the lives of stars.”Astronomy today, 2000.
King, Tom. “Stages in the Life Cycle of a Star.”Ehow, 1999.
Newman, Phil et al. “What Is a Star?”NASA, 2010.
Night Sky Observer. “New View of Family Life in the North American Nebula.”Night Sky Observer, 2011.