Blue supergiant stars are staller evolutions that have resulted over millions of years. Stars during the main sequence phase spend a majority of their lives. During the main sequence stage, the star converts hydrogen to helium by nuclear fusion in the cores of stars the process also known as proton-proton chain. After spending of hydrogen fuel, the star will collapse and heat up rapidly causing the outer layers to expand inwards. When the core is very hot, the energy spreads through the interior of the star’s large surface area. The different fusion rates of different elements vary wildly to the point where the fusion process slows down to make stars become blue supper giants (Ohyama and Hota 1).
Blue supergiant stars are the most massive stars that are found in the universe with a mass 20 times that of the sun. These blue stars are very hot with between 20,000 and 50,000 kelvin surface temperature. The best known example of these stars is Rigel that is found in Orion constellation. The red supergiant can turn into blue supergiant. When the star is more compact and smaller their luminosity are in smaller surface areas making them much hotter resulting in a blue supergiant phase. After this, they will extend and become large sizes with wider area luminosity.
These stars have helium proportions and when they are at high proportions, they rotate at a faster pace. They are generally exhibited by a mixture of different elements in their spectra that depends on the efficiency of nucleosynthesis and type of elements (Ohyama and Hota 2).
They are characterized by large sizes among all stars with a typical radius of between 200 and 800 times that of the sun making them the most massive star in the universe. The blue supergiant stars though sparse are very fast and very rare to occur. One example of a blue supergiant is the Rigel star which is the brightest of all. It has 75 times radius of the sun. The Rigel star has a three star system consisting of a blue supergiant Rigel A and two dimmer and distant companions.
Its energy is emitted as invisible infrared 40000 brighter than the sun and its fuel exhausts at a quicker rate and thus exists for a few million years of around 8 million. Its estimated mass is about 18 times the mass of the sun with its temperatures ranging up to 22000 F. The blue supergiant stars can also boil off their surfaces through the process known as stellar wind and, this wind flows a thousand faster than the red supergiant though they are less violent as compared to a supernova explosion (Marschall).
Another example is the 29 Canis Majoris of a Beta Lyrae variable. It is located at a distance of 3000 light years; its luminosity is 63000 L and a radius of 13/10R and a temperature of 29, 000K (Marschall). The Zeta Puppit, Naos, formed at Vela region is understood to be closer to the Earth with a Puppis constellation and luminosity of 55000L, radius of 14L and a temperature of 42000K (Marschall).
As a result of dynamic events in the universe, blue supergiant star can die. These results in a form of intense explosions emitted to the entire galaxies leaving behind powerful, compact objects. The stars occur in the main sequence which begins with initial star formation where the core is ignite through nuclear fusion that stops when the hydrogen is exhausted and heavier element fusion has begun (Kundt). Then the stars will follow a particular path depending on its mass. This occurs mostly in the red supergiant phase and possibly in the blue supergiant state which is rare.
Reference
Marschall, Laurence A. The supernova story. Princeton, N.J. : Princeton University Press, 1988. Print.
Ohyama, Youichi and Ananda Hota. "Discovery of a Possibly Single Blue Supergiant Star in the Intra-cluster Region of Virgo Cluster of Galaxies." The Astrophysical Journal Letters. 767 (2013): 2. Web <http://iopscience.iop.org/2041-8205/767/2/L29/>
Kundt, Wolfgang. Neutron Stars and Their Birth Events. Dordrecht: Kluwer Academic Publishers, 1990. Print.
