Life cycle of a star
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Life cycle of a star



Hi, my name is Ben Ten living in North America. I am a student of Bachelors Part – II and a book wormer. I interested in astronomy and I prefer to search for information about astronomy. I want to ...

Hi, my name is Ben Ten living in North America. I am a student of Bachelors Part – II and a book wormer. I interested in astronomy and I prefer to search for information about astronomy. I want to have some necessary knowledge about astronomy. I especially draw my attention in Planet Star. I introduce my website, which contain the useful information about Star planet and some Facts about planet Star. There are also some pictures of Star. I hope that, they will provide to you useful knowledge about astronomy in general and STAR in particular.



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Life cycle of a star Document Transcript

  • 1. Life Cycle of a Star – Birth through to Death The life cycle of a star is an amazing scientific phenomenon that takesbillions and billions of years to occur and involves several stages each with itsown interesting characteristics. Before we delve deeply into the various processinvolved in the creation of a star, let us first try to define what a star actually is. Astart is a luminous globe of gas that is capable of producing its own heat and lightthrough nuclear fusion. It is created from a nebula, which is a cloud of hydrogenand helium gas as well as dust existing in space. The life cycle of a star begins with the nebula. It is known as the birthplace of stars, the nebula is known to have several kinds. Basically, stars are formed from the gases that are contained within the nebula. These clouds of gases – hydrogen and helium – and dust collapse due togravitational forces resulting to the formation of protostars. Protostars which are known as young stars eventually collapse in order toform main sequence stars or also called dwarf stars. A red dwarf star is small andfaint approximately tenth of the diameter of the Sun. These burn slowly and live toabout a hundred billion years. These would eventually expand as they begin to grow old; as time goes on;its core runs of hydrogen and helium gases. This results in the cooling of the starand a decrease in its brightness, this star is now known as the red giant. The red giant or can also be called the red super giant is a large bright starthat has a cooler surface temperature – 2,000 to 3,000oC. They are considered
  • 2. bright due to their size although the core temperature is quite low. The red giantcollapses in time leading to a massive explosion known as the Supernova. Thewhite dwarf star is part of the last stage of the life cycle of a star after the redgiant. A perfect example of this would be the Sun. Depending on the star’s original mass, it can have several fates: Black dwarf The black dwarf is considered as a stellar remnant that has lost its heat due to the depletion of the helium and hydrogen gases from its core. It commonly arises from the white dwarf star. Neutron Star This type of star occurs after a supernova. It results from the combination of protonsand electrons leading to the formation of the neutron star. According to studies, ifthe mass of a neutron star further decreases, there is a possibility that the increasein gravitational pull can result to the creation of a black hole. Black Hole These are believed to form from massive sized stars when their lifespan ends.It is believed that due to the intense gravitational pull within the black hole, noteven light can escape it. The density of matter within a black hole is immeasurablesince they can distort the space surrounding them and suck in the matter nearby.
  • 3. Stars – Celestial Objects On Sea and Sky For as long as mankind can remember, stars have been those celestial objectson sea and sky that have stirred up a lot of theories with regards to what they areand how they came to be. Constellations are known as the chance aligning of thestars that form several various icons coming from the ancient times. Theseconstellations are utilized by astronomers in order to provide organization to the skies at night and to properly locate the stars. Stars are considered as the most numerous visible objects in the universe. The light and energy emitted by these objects are considered as a power source for the solar system. Also coming from the star are the heavy elements that are essentialcomponents in the formation of life forms. They are a keystone piece in thecreation of life in the universe. Without them, the universe would cease to exist asis. A perfect example of a star that provides energy to life forms would be theSun. The Sun as we know, gives life to Earth through the energy and heat itprovides for all the living species on the planet. Energy and heat are essentialfactors for the survival of our species against the coldness of outer space. So it brings us to the question, does the brightness of a star have any relationto its core temperature? The measure of the stars brightness is termed as itsmagnitude and identifying the colour to determine the temperature. Astronomershave developed a scale to determine the magnitude and temperature of a star basedon its characteristics.
  • 4. For the magnitude, the lower the value of the number given, the brighter thestar is. As for the colour and temperature, stars are divided among their colour andranked in what is called a spectralclass. This is an array of variousstars beginning from Class Owhich is blue to the Class M thatare red. The hotter and higher thetemperature of the star, the moreintense shade of blue it is. Whilestars that are red in colour, fallunder the category of coolertemperatures. Contrary to popular belief, stars in the sky do not really twinkle. Theoccurrence of the phenomenon that makes stars seem to twinkle is a direct effectfrom the interference in atmosphere. Air emitted rises, which causes images wesee to wave and blur. Stars that are lower in position in the sky have moretendencies to twinkle in comparison to those that are in a higher location. The twinkling effects of celestial objects on sea and sky are more likely tooccur in lower located stars since more light is required to pass through theplanet’s atmosphere. A good analogy or comparison would be in the case of a hotsummer day. Upon gazing far out into the pavement, there is a tendency for theroad to blur or seem to move. It is actually the hot air escaping from the pavementand into the atmosphere. Stars – The Solar System and Outer Space Probably among all the famous stars within the solar system and outerspace, the most popular would have to be the sun. The sun actually comprises ofalmost all the matter within the solar system, the remaining matter would be
  • 5. composed of the planets Jupiter andSaturn. Within the solar system andouter space, there are numerousastronomical objects that are bound tothe orbit through the force of gravity. Stars are among the mostabundant astronomical objects that laywithin the entirety of the solar system.Created from space formations termedas nebula, these stars live for billionsof years as glowing structures ofburning gas. As the star ages, its coretemperature becomes cooler and the entire structure becomes unstable. Theinstability of an aging star eventually leads to its death in a massive explosionknown as the supernova. The particles and elements coming from these stars explosions are the coreingredients that ultimately become new stars when they combine with other gasesand dust. This occurrence is a perfect example of where energy is neitherdestroyed nor created. It only changes in form. Eventually the increase of the pull of gravity forces the creation of brand newstars. The increase in gravitational force is due to the spinning action created bythe clouds of dust, hydrogen and helium gases. These are the initial stages of theformation of a new star. If you wonder why stars are so bright, you can compare the mechanism of astar to that of a nuclear reactor. A massive amount of energy is being produced bystars through nuclear fusion involving helium and hydrogen gas molecules. This isthe source of the brightness of a star. Surprisingly, there are about two hundred billion stars within the knownuniverse. That does not even include the sun! Since the sun is the nearest star to
  • 6. our planet, we are able to observe its natural form as a glowing hot ball of gas.While we look at other stars in the sky as small little dots resembling lights on aChristmas tree. They seem tiny when in fact these stars can be as massive or evenmuch more in comparison to our Sun. It is only due to their extreme distance which makes them difficult to see in their actual form. To give you a better idea on how massive another star can be, the Sun is actually just a medium sized star. While our planet, in terms of the diameter is only a hundredth of that of the Sun. So imagine another star that is twice or more in size of the Sun, big huh? Giant stars are aboutone thousand times the diameter of the Sun. These are found in several differentgalaxies that are billions of light years away. So the next time you look up in that night sky and you see a star twinkle,imagine how many light years it took for that light to travel. Imagine that the staryou’re looking at is only a minute part of an even bigger picture. Interesting Facts about Stars The night sky is filled with a lot of mysteries and trivial information. Thereare a lot of interesting facts about stars that you may not know of. Knowingabout these trivial facts can actually help you to appreciate the universe more orcan be an interesting topic for conversation between you and your peers. So hereare some interesting facts about stars: 1. The Sun is the closest star to Earth.
  • 7. For those that don’t know, yes, the Sun is a star! It is the closest one to theplanet - approximately 150 million kilometers away. The Sun is classified underthe G2 yellow dwarf star class and is in the phase of its life cycle known as themain sequence. Our Sun, like most other stars, emits energy and light throughconversion of hydrogen and helium atoms. This process – nuclear fusion – occursat the Sun’s core where it’s the hottest. The Sun is estimated to be about 4.5 billion years old and is predicted to be in this phase for another seven billion years or so. Unfortunately, like most other stars, when the time comes that it runs out of fuel, it would become a red giant star while increasing in size. There is even a probability that it would engulf Mercury, Venus and probably even Earth as it expands. 2. All stars are in a perfect state of balance. Since they are billions of light years away, it would be difficult to know thatstars are actually in a constant battle or conflict with themselves. All the stars havetheir own gravitational pull that pulls itself inward. This action, if not repelled byanother force would lead to the continuous collapse of a star until it becomesminute in size. The amazing part is that the nuclear fusion occurring at the star’score actually repels the gravitational force by creating an outward push. Thisphenomenon actually takes about 100,000 years to complete.
  • 8. When a star loses its fuel at the core, there is no longer any action to repel thepull of gravity hence a star collapses into smaller minute particles known asdwarfs. 3. Everything is equal. With stars, the colour, temperature and its mass are all related. The actual color of a star can indicate its size and temperature. The hottest stars are surprisingly the smallest ones and are blue in colour.Their temperatures go to about 12,000 Kelvin. While the yellow coloured stars arethe medium sized ones just like the Sun. Their temperatures fall to about 6,000Kelvin. And lastly, the coolest and biggest ones are coloured red and havetemperatures that are less than 3,500 Kelvin. 4. Stars are just like twins. When looking at the night sky, it would seem like stars are up there all alone.But don’t fret; these heavenly bodies actually come in pairs. These are termedbinary stars where in a set of two stars share a common center of gravity in anorbit. In some other systems in space, stars can even come in groups of threes oreven four!