When one looks at the sky, stars are the most identifiable astronomical objects in the galaxy. Many studies are carried out to find out about the formation, distribution, dynamics and composition of the stars (young). Stars have a propensity to exist in dusts that are spread all over most galaxies. Orion Nebula is one good example of such dust clouds. Within these dust clouds are strong turbulence that leads to formation of knots that are characterized with ample mass of dust and gas that would ultimately disintegrate due to its own force.
In the process of their collapse, the materials at the centre would blaze. This material is known as the protostar and with time it would become a star (young). In the galaxy, stars appear either in multiples or in pairs, this is due to the breaking away of the collapsing dust and gas into three or two lobs.
The hot core around the collapsing cloud starts to gather dust and gas, and in the end it forms part of the star. The parts that would not form the star but develop into planets or asteroids, or would just remain dust. The formation starts when heavier parts of the dust cloud commence to cave in because of their own gravity or weight (young).
The cloud core generally has a solar accumulation of about 10000 in the outward appearance of dust and gas. The outer clouds are less dense as compared to the core; this explains why the core collapses first (young). The collapse of the core leads to the formation of small fragments called the clumps. The clumps are the ones that would turn to protostars in a progression that can last for around 10 million years.
The mass that has broken from the cloud core, with its own uniqueness and gravity is known as the protostar. As it forms, gas collects at its centre which produces kinetic energy. This force is in the form of heat making the stress and the hotness at the centre to rise to thousands of degrees (Schneider & Arny).
Image as portrayed in Schneider & Arny
During the initial stages, the clump responsive to radiation because it is transparent and the process are fairly quickly. The clump gradually becomes dense hence opaque and stops responding to radiation effects (Schneider & Arny). The escaping rays from the inside is trapped and the stress and hotness of the central region increases. The increase would continue and pressure inside would stop inflow or more loose gas into the protostar and it becomes stable.
After the protostar is stable, it becomes a hydrogen-burning star and forms a powerful airstream along its rotation axis. This explains why many stars in their early phases of development have the bipolar outpouring of gas.
Image as portrayed in Schneider & Arny
The collapse leads to massive, opaque disks around the star during this phase. The disks radiate energy from the infrared wavelengths and ultraviolet and optical wavelengths. On the exterior of the youthful stars are black spots which resemble spots of the sun but cover larger face of the young star. (Schneider & Arny) The T-Tauri phase is characterized by strong solar winds, spirited surface activities like eruptions and flares, and irregular and variable light curves.
From the fall down of the cloud to the adulthood of a star big as the sun could be as long as fifty million years. It could then remain in that state for about 10 billion years. Today, many studies are carried out to shed more light on the formation of the stars and more interesting breakthroughs have been made on this issue (Schneider & Arny). The evolution of stars is described by the position they take on a graph known as the Hertz Sprung-Russell, this is like the periodic table of various elements but instead of the elements, it has the star positions.
Deep in the core of the stars, helium is present and it results mainly from the nuclear synthesis of hydrogen. The energy that flows out from the central region of the star provides pressure that enables it to remain afloat and never to collapse because of its own weight and the same energy gives the start its shiny appearance. On the Hertz Sprung-Russell diagram, one would notice some stars that appear on the main sequence (NASA). These stars are characterized by a broad assortment of colors and luminosities and these are the same distinctiveness that can be used to classify them.
Red dwarfs are the tiniest stars are made of a mass that is 10% that of the sun. Their energy emission is also low at only 0.01% and could be seen glowing feebly with a temperature of 3000-4000k (NASA). These small stars however form the largest number of stars in the galaxy and their lifespan could span to more than ten billion years.
Hyper giants, on the other hand, are the enormous stars and are thought to be over a hundred times huge than the sun. The surface temperatures of these massive stars are 30000k and their energy emission is more than 1000 times that of the sun. Their lifespan is however fewer as weighed against other stars as it exists only for a few millions of years (NASA). These stars used to dominate the skies in the early universe but only handful of them exist in today’s Milky Way galaxy
From the above discussion, it is clear that larger stars have shorter lifespan. When all the hydrogen in the center of the star has been compounded, the nuclear responses stop. The reaction provides energy necessary for the existence of the stars and deprivation of this energy leads to collapse of the center which in turn becomes hotter (NASA). The available hydrogen in the external core of the stars ensures sustained fusion in the case around the core.
The hot inner core continues to get hotter and in the process push outer layers outside making the start to expand, cool and the change into a red giant. Sufficiently massive star would have their core become much hotter that they can even support nuclear reactions that uses helium while giving out various heavy elements including iron. Such responses however never last and are only for momentary reprieve. Eventually the nuclear fires inside the star becomes unsteady, burns furiously and even die down. The disparities of the heat would make the star pound and scatter its external covers. Whatever follows after this would depend on the size of the star’s core
Innovative scientists at the zooniverse have been able to discover some hidden phases that were in the past absent from the diagrams of star formation. The recent discovery showed that before stars to be emerge from their dusty forms, the first grow to form dense, cool gas before they form protostars which are ready to burn and heat up materials in their surrounding in the process. One of citizens was able to classify bubbles from the detailed image of a star at the gallery of the spitzer space telescope (“NASA”). He was not able to classify it and so he opted to post it on the zooniverse discussion forum
A professional astronomer tagged the image as yellow ball. It showed natural molecules and a warm radiant dust releasing green and red matter respectively. It is understood that these emissions formed what was earlier missing in the transition of stars from clumps of chilly gas and dirt to new stars.
One factor that points out to the importance of studying star formation is the invention of machines to help scientists during their studies (“Propulsion”). This method, generally identified as the machine learning helps in understanding detailed properties of the stars in the galaxy. The machines help much in sorting through the millions of stars that exist in the galaxy and in learning of their compositions, sizes and various traits. Machine learning is part of the ever-growing research in which large data sets from computers are used by the scientists to find patterns that would otherwise be overlooked or missed by human beings.
Before machine learning, scientists used detailed spectrum in which starlight is shifted into various wavelengths which was slower as compared to machine learning (“Propulsion”). The computer algorithms flip through the existing stacks of images very quickly and in the process identify different patterns that show the properties of stars.
NASA.” Stars” http://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve/. Internet Resource
Propulsion Laboratory. ”Machines teach Astronomers about stars” Astronomy. 13 Jan, 2015. < http://www.astronomy.com/news/2015/01/machines-teach-astronomers-about-stars>. Internet Resource
Young, Monica. “Yellow balls: A New View of Star Formation” SkyandTelescope. 2 February, 2015. < http://www.skyandtelescope.com/astronomy-news/yellowballs-new-view-star-formation-0202151/>. Internet Resource