Stars: The Importance Of The Sun

Since the Ancient Time, man has always got curious about tiny sparkling objects in the night sky called stars; and has never stopped doing research to discover what they mean and how they affect to human’s life. Nowadays, by studying stars, man could understand more about the Sun which plays an important role in people, plants and animals on the Earth. It also helps us know how our Solar system was formed, which might give us a chance to discover other signs of the living things in this vast universe.

Stars in our vast universe begin from dust and gases called molecular clouds. At the beginning, these clouds are at a very low temperature (about 10 to 20 K) with a mass of 2.1013 kg (equals to 1000 solar masses). The deep cold makes these gases

When the temperature finally exceed 10 million K, thermonuclear fusion would happen. The great energy released by this nuclear fusion would make the star shine brightly and now become a “real” star. We would call these type of stars “main sequence”. Low mass stars (about a half masses of our Sun) are the smallest, coolest and dimmest stars in the Main Sequence. They are usually in red or brown colors. Intermediate mass stars, like our Sun, are in the middle of the Main Sequence and would have orange or yellow colors. High-mass stars (about 15 times massive than the Sun) are the biggest, hottest and brightest stars in this sequence. These stars are usually blue, blue-white or white in

This state would last for about thousand years before the core contracts due to the lack of fuel and spread a layer of dust called nebula. Sometime this layer could “swallow” some nearby planets and is consequently called the planetary nebula. The core now would become a white dwarf. Gradually, the white dwarf would become cooler and finally turns a black dwarf - a real death star. However, if a white dwarf is not so far to another Red Giant, it may create a supernovae. The core of this white dwarf now with a great density (about 4.109 kg/m3) would take the energy from its neighbor to begin the thermonuclear fusion and lead to a collapse. A supernovae now is created and releases elements even heavier than iron (Fe). These type of supernovae is called supernovae type I - to distinguish with the supernovae from massive stars.

Meanwhile, massive stars would turn Supergiant stars after the loss of masses due to thermonuclear fusion. At this time, massive stars with masses between Mc and MSun would become neutron stars. A neutron star usually have a small radius and consequently spin with a significant speed. It also have a strong magnetic field that emits electromagnetic wave in range of radio. Hence a neutron star is also called a pulsar. Besides, the collapse that forms a neutron star also complies with a supernova type