Slide 1
Presentation on the topic: “Internal structure of the Sun” Completed by a student of class 11 “a” GBOU secondary school 1924 Governors AntonSlide 2
Slide 3
The Sun is the only star in the Solar System around which other objects of this system revolve: planets and their satellites, dwarf planets and their satellites, asteroids, meteoroids, comets and cosmic dust.
Slide 4
Structure of the Sun: -Solar core. -Zone of radiative transfer. -Convective zone of the Sun.
Slide 5
Solar core. The central part of the Sun with a radius of approximately 150,000 kilometers, in which thermonuclear reactions occur, is called the solar core. The density of the substance in the core is approximately 150,000 kg/m³ (150 times higher than the density of water and ~6.6 times higher than the density of the densest metal on Earth - osmium), and the temperature in the center of the core is more than 14 million degrees.
Slide 6
Radiative transfer zone. Above the core, at distances of about 0.2-0.7 solar radii from its center, there is a radiative transfer zone in which there are no macroscopic movements; energy is transferred using photon re-emission.
Slide 7
Convective zone of the Sun. Closer to the surface of the Sun, vortex mixing of the plasma occurs, and the transfer of energy to the surface is accomplished primarily by the movements of the substance itself. This method of energy transfer is called convection, and the subsurface layer of the Sun, approximately 200,000 km thick, where it occurs is called the convective zone. According to modern data, its role in the physics of solar processes is exceptionally great, since it is in it that various movements of solar matter and magnetic fields originate.
Slide 8
Slide 9
Photosphere of the Sun. The photosphere (the layer that emits light) forms the visible surface of the Sun, from which the size of the Sun, the distance from the surface of the Sun, etc. are determined. The temperature in the photosphere reaches an average of 5800 K. Here, the average gas density is less than 1/1000 of the density of the earth's air.
Slide 10
Chromosphere of the Sun. The chromosphere is the outer shell of the Sun, about 10,000 km thick, surrounding the photosphere. The origin of the name of this part of the solar atmosphere is associated with its reddish color. The upper boundary of the chromosphere does not have a distinct smooth surface; hot emissions called spicules constantly occur from it. The temperature of the chromosphere increases with altitude from 4000 to 15,000 degrees.
Solar core. The central part of the Sun with a radius of approximately kilometers, in which thermonuclear reactions occur, is called the solar core. The density of the material in the core is approximately kg/m³ (150 times the density of water and ~6.6 times the density of the densest metal on Earth, osmium), and the temperature in the center of the core is more than 14 million degrees.
Convective zone of the Sun. Closer to the surface of the Sun, vortex mixing of the plasma occurs, and the transfer of energy to the surface is accomplished primarily by the movements of the substance itself. This method of energy transfer is called convection, and the subsurface layer of the Sun, approximately km thick, where it occurs is the convective zone. According to modern data, its role in the physics of solar processes is exceptionally great, since it is in it that various movements of solar matter and magnetic fields originate.
Photosphere of the Sun. The photosphere (the layer that emits light) forms the visible surface of the Sun, from which the size of the Sun, the distance from the surface of the Sun, etc. are determined. The temperature in the photosphere reaches an average of 5800 K. Here, the average gas density is less than 1/1000 of the density of the earth's air.
Chromosphere of the Sun. The chromosphere is the outer shell of the Sun, about km thick, surrounding the photosphere. The origin of the name of this part of the solar atmosphere is associated with its reddish color. The upper boundary of the chromosphere does not have a distinct smooth surface; hot emissions called spicules constantly occur from it. The temperature of the chromosphere increases with altitude from 4000 to degrees.
Crown of the Sun. The corona is the last outer shell of the Sun. Despite its very high temperature, from up to degrees, it is visible to the naked eye only during a total solar eclipse.
Slide 1
Slide 2
Internal structure of stars Sources of energy of stars If the Sun consisted of coal and the source of its energy was combustion, then if the current level of energy emission were maintained, the Sun would completely burn out in 5000 years. But the Sun has been shining for billions of years! The question of the energy sources of stars was raised by Newton. He assumed that stars replenish their energy reserves from falling comets. In 1845 German Physicist Robert Meyer (1814-1878) tried to prove that the Sun shines due to the fall of interstellar matter onto it. 1954 Hermann Helmholtz suggested that the Sun emits some of the energy released during its slow compression. From simple calculations we can find out that the Sun would completely disappear in 23 million years, and this is too short. By the way, this source of energy, in principle, occurs before the stars reach the main sequence. Hermann Helmholtz (1821-1894)
Slide 3
Internal structure of stars Sources of stellar energy At high temperatures and masses greater than 1.5 solar masses, the carbon cycle (CNO) dominates. Reaction (4) is the slowest - it takes about 1 million years. In this case, a little less energy is released, because more than it is carried away by neutrinos. This cycle in 1938 Developed independently by Hans Bethe and Carl Friedrich von Weizsäcker.
Slide 4
Internal structure of stars Sources of energy of stars When the combustion of helium in the interior of stars ends, at higher temperatures other reactions become possible in which heavier elements are synthesized, up to iron and nickel. These are a-reactions, carbon combustion, oxygen combustion, silicon combustion... Thus, the Sun and planets were formed from the “ashes” of supernovae that erupted long ago.
Slide 5
Internal structure of stars Models of the structure of stars In 1926 Arthur Eddington’s book “The Internal Structure of Stars” was published, with which, one might say, the study of the internal structure of stars began. Eddington made an assumption about the equilibrium state of main sequence stars, i.e., about the equality of the energy flux generated in the interior of the star and the energy emitted from its surface. Eddington did not imagine the source of this energy, but quite correctly placed this source in the hottest part of the star - its center and assumed that a long time of energy diffusion (millions of years) would level out all changes except those that appear near the surface.
Slide 6
Internal structure of stars Models of the structure of stars Equilibrium imposes strict restrictions on a star, i.e., having reached a state of equilibrium, the star will have a strictly defined structure. At each point of the star, the balance of gravitational forces, thermal pressure, radiation pressure, etc. must be maintained. Also, the temperature gradient must be such that the heat flow outward strictly corresponds to the observed radiation flow from the surface. All these conditions can be written in the form of mathematical equations (at least 7), the solution of which is possible only by numerical methods.
Slide 7
Internal structure of stars Models of the structure of stars Mechanical (hydrostatic) equilibrium The force caused by the pressure difference, directed from the center, must be equal to the gravitational force. d P/d r = M(r)G/r2, where P is pressure, is density, M(r) is mass within a sphere of radius r. Energy equilibrium The increase in luminosity due to the energy source contained in a layer of thickness dr at a distance from the center r is calculated by the formula dL/dr = 4 r2 (r), where L is luminosity, (r) is the specific energy release of nuclear reactions. Thermal equilibrium The temperature difference at the inner and outer boundaries of the layer must be constant, and the inner layers must be hotter.
Slide 8
Internal structure of stars Internal structure of stars 1. The core of a star (zone of thermonuclear reactions). 2. Zone of radiative transfer of energy released in the core to the outer layers of the star. 3. Convection zone (convective mixing of matter). 4. Helium isothermal core made of degenerate electron gas. 5. Shell of ideal gas.
Slide 9
Internal structure of stars Structure of stars up to solar mass Stars with mass less than 0.3 solar are completely convective, which is associated with their low temperatures and high absorption coefficients. Solar-mass stars undergo radiative transport in the core, while convective transport occurs in the outer layers. Moreover, the mass of the convective shell quickly decreases when moving up the main sequence.
Slide 10
Slide 11
Internal structure of stars Structure of degenerate stars Pressure in white dwarfs reaches hundreds of kilograms per cubic centimeter, and in pulsars it is several orders of magnitude higher. At such densities, the behavior differs sharply from that of an ideal gas. The Mendeleev-Clapeyron gas law ceases to apply - pressure no longer depends on temperature, but is determined only by density. This is a state of degenerate matter. The behavior of a degenerate gas consisting of electrons, protons and neutrons obeys quantum laws, in particular the Pauli exclusion principle. He claims that more than two particles cannot be in the same state, and their spins are directed oppositely. For white dwarfs, the number of these possible states is limited; gravity tries to squeeze electrons into already occupied spaces. In this case, a specific counter-pressure force arises. In this case, p ~ 5/3. At the same time, electrons have high speeds of movement, and the degenerate gas has high transparency due to the occupancy of all possible energy levels and the impossibility of the absorption-re-emission process.
Slide 12
Internal structure of stars The structure of a neutron star At densities above 1010 g/cm3, the process of neutronization of matter occurs, the reaction + e n + B. In 1934, Fritz Zwicky and Walter Baarde theoretically predicted the existence of neutron stars, the equilibrium of which is maintained by the pressure of the neutron gas. The mass of a neutron star cannot be less than 0.1M and more than 3M. The density at the center of a neutron star reaches values of 1015 g/cm3. The temperature in the interior of such a star is measured in hundreds of millions of degrees. The sizes of neutron stars do not exceed tens of kilometers. The magnetic field on the surface of neutron stars (millions of times greater than the Earth's) is a source of radio emission. On the surface of a neutron star, the matter must have the properties of a solid body, i.e., neutron stars are surrounded by a solid crust several hundred meters thick.
Slide 13
M.M. Dagaev and others. Astronomy - M.: Education, 1983 P.G. Kulikovsky. Handbook for an Astronomy Amateur - M.URSS, 2002 M.M. Dagaev, V.M. Charugin “Astrophysics. A book for reading on astronomy” - M.: Prosveshchenie, 1988. A.I. Eremeeva, F.A. Tsitsin “History of Astronomy” - M.: Moscow State University, 1989. W. Cooper, E. Walker “Measuring the light of stars” - M.: Mir, 1994. R. Kippenhahn. 100 billion suns. Birth, life and death of stars. M.: Mir, 1990. Internal structure of stars References
The structure of the sun Here you can quickly download the presentation + Word file for it. At the top, click skip ad (after 4 seconds)
Solar core The central part of the Sun with a radius of approximately kilometers, in which thermonuclear reactions occur, is called the solar core. The density of the substance in the core is approximately kg/m³.
Chromosphere of the Sun The chromosphere of the Sun (colored sphere) is a dense layer (km) of the solar atmosphere, which is located directly behind the photosphere. The chromosphere is quite problematic to observe due to its close location to the photosphere. It is best seen when the Moon covers the photosphere, i.e. during solar eclipses.
Solar prominences Solar prominences are huge emissions of hydrogen that resemble long luminous filaments. The prominences rise to enormous distances, reaching the diameter of the Sun (1.4 million km), move at a speed of about 300 km/sec, and the temperature reaches degrees.
Loading...