Chandrasekhar limit refers toWhite dwarfThe highest quality of about 3 × 10thirtyKg, yesSolar mass1.44 times.This limit was calculated by Chandraseka.The calculation results will be based onNucleusAnd temperature.
Is a constant related to the Ryan Enten equation. In numerical terms, this value is about (2/μe)two· 2.85 ×10thirtyKg, or 1.43 (2/μe)twoM⊙, where M⊙=1,989×10thirtyKg is the standard solar mass, and
yesPlanck mass，MPI≈2.176×10-8Kg is MOrder of magnitudeLimit MPlthree/mHtwo。As long as the Chandraseka limit is exceeded, a white dwarf may become an object with a volume of 0 but a density of ∞.
Brief application
The heat generated by stars willatmosphereMove outward.When the energy of a star is exhausted, its atmosphere will collapse back to the surface of the star under the influence of its gravity.If the mass of the star is less than the Chandraseka limit, the collapse will be affectedElectronic degeneracy pressureTherefore, a stable white dwarf is obtained.If its mass is higher than Chandraseka limit, it will shrink and becomeneutron star, black hole or theoreticalQuark star。
Of the maximum possible mass of a stable cold starcritical valueIf a star with more mass than this, it will collapse into a black hole.
Research process
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Discovery process
Chandraseka, Subramanian
In 1928, an Indian graduate student——Chandraseka, SubramanianCome to England by boatCambridgeWith Sir Arthur Eddington, a British astronomerGeneral relativityHome).(It is recorded that in the early 1920s, a reporter told Eddington that he heard that only three people in the world could understand the general theory of relativity. Eddington paused for a moment and then replied, "I'm thinking about who the third person is.") On his trip to Britain from India, Chandraseka calculated that after running out of all fuel,How big a star can continue to resist its own gravity and maintain itself.The idea is that when the star is smaller, the material particles are very close, and according to Pauli'sIncompatibility principleThey must have very different speeds.This causes them to diverge from each other and attempt to expand the star.A star can keep its radius unchanged due to the balance of repulsion force caused by gravitational action and incompatibility principle, just as gravity was balanced by heat in its early life.
However, Chandraseka realized that there was a limit to the repulsive force that the exclusion principle could provide.The largest particle in a starSpeed differenceLimited to the speed of light by relativity.This means that when the star becomes compact enough, the repulsion force caused by the incompatibility principle will be smaller than that caused by gravity.Chandraseka calculated that: one is aboutSolar massOne and a half times of the cold stars cannot support themselves to resist their own gravity, which is called the Chandraseka limit.Soviet UnionScientist Lev Davidovich·LandauSimilar findings were made almost simultaneously.
Significance
This pairHigh qualityThe final destination of stars is of great significance.If a star'smass ratioThe Chandraseka limit is small, and it will finally stop shrinking and finally become a star with a radius of thousands of miles and a density ofCubic inchHundreds of tons“White dwarf”。The white dwarf is between the electrons in its matterIncompatibility principleSupported by repulsive force.We have observed a large number of such white dwarfs.The first one was observed around the brightest star in the night sky——SiriusThe rotating one.
Stellar morphology
LandauIt is pointed out that there is another possibleFinal state。hisUltimate massIt is about twice the mass of the sun, but its volume is even more thanWhite dwarfIt's much smaller.These stars are supported by the repulsive force of the incompatibility principle between neutrons and protons, not electrons.So they are calledneutron star。Their radius is only about 10 miles, and their density is several hundred million tons per cubic inch.When neutron star was first predicted, there was no way to observe it.In fact, they were observed a long time later in 1967.
remaining problems
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On the other hand, when stars whose mass is greater than the Chandraseka limit run out of fuel, there will be a big problem: under certain circumstances, they will explode or throw out enough material to reduce their mass below the limit to avoid catastrophicGravitational collapse。But it is hard to believe that this will happen no matter how big the star is.How do you know it must lose weight?Even if each star tries to lose enough weight to avoid collapse, if you add more mass toWhite dwarforneutron starWhat will happen if we make it exceed the limit?Will it collapse to infinite density?Eddington was shocked and refused to believe Chandraseka's results.Eddington believes that a star cannot collapse into a point.This is the view of most scientists: Einstein himself wrote a paper announcing that the volume of the star would not shrink to zero.Other scientists, especially his former teachersStellar structureThe main authority of——Eddington The hostility made Chandraseka abandon this work and turn to research such asStellar clusterSports and other astronomical issues.However, he was awarded in 1983Nobel PrizeAt least partly because of what he did in his early yearsCold starQuality limit of the work.Chandraseka pointed out that,Incompatibility principleThe collapse of a star whose mass is greater than the Chandraseka limit cannot be prevented.
