How the pauli exclusion principle regulates the evolution of stars reading?
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Now, the Pauli Exclusion Principe states that “no two identical particles can occupy the same quantum state” (9) (Kaufmann, 1994): that is, loosely, they cannot have the same spatial location and momentum. This prin-ciple is important in determining the ulti-mate fate of stars. Consider low Main Sequence mass stars( this is, stars of less than three solar masses) which have passed through the hydrogen- burning phase to he-lium-burning. Such bodies require extreme compression of the core to raise their tem-perature sufficiently for the onset of he-lium-burning. Increasing desity of elec-trons occurs, so that they are squashed into close proximity with each other, until a limit is reached when they resist any further compression. This phenomenon is called de-generacy, and is a manifestation of the Pauli Exclusion Principle (8). Resistance to further compression results in degenerate- electron pressure which supports the core, prevent-ing its contraction. However, this pressure is independent of temperature continues to increase. Helium ignition takes place and the thermonuclear reaction proceeds at an increasing rate until a helium-flash occurs. The temperature is so great that degeneracy cannot be maintained: the core suddenly ex-pands with a corresponding decrease in temperature that abruptly ends the he-lium-flash. This cycle may be repeated until all the core helium is converted to carbon.
More massive stars do not undergo a be- lium-flash (10). Moreover, their cores are suffi-ciently massive for further element-burning to occur, until they, too, reach a limit im-pased by degeneracy. That is, as the pro-duct of each phase of element-burning is al-ways nuclei of greater mass, it requires even greater compression of the core remnant in order to raise the temperature sufficiently high enough to initiate the next phase. Such compression can only occur until the degen-erate condition is achieved.
Stellar death comes about when the core cannot carry out further element-burning, because of its degenerate nature. Stars of Main Sequence mass less than seven solar masses become white dwarfs (12). The stability of a white dwar5f is only maintained if its final(post- Main Sequence) mass does not exceed the Chandrasekhar Limit of 1.4 solar masses. Degenerate-electron pressure supports the core against collapse, thereby conforming to the Principle.
Neutron stars (13) are the stellar corpses of stars whose Main Sequence mass is between seven and twenty solar masses. Before death, these stars have undergone some fur-ther element-burning and the final core mass exceeds the Chandrasekhar Limit. This is too great for degeneracy equilib-rium is achieved once more. It is degener-ate-neutron pressure that halts the collapse, and, thereby, upholds the Principle.
The most massive stars have completed burn-ing to obtain an iron core, and have a Main Sequence mass exceeding twenty solar masses. This is so great that degener-ate-neutron pressure cannot support it, and rapid collapse ensues. Since density is in-versely proportional to volume and the mass is vast, then, as the volume dwindles, the density tends to infinity and a Black Hole is formed (14).
Black Hole are a violation of Pauli’s Ex-clusion Principe. If the Principle did not regulate the evolution of stars, nothing would prevent the inexorable collapse of an inter-stellar cloud from its initial disturbance into a massive Black Hole.
Wolfgang Pauli developed a principal which is known as the Pauli exclusion principal. According to the principal, no two electron has the same quantum number distributed in the atom. The summary of the principal states that in an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins thus they couldn't have same quantum number.