HR diagram ppt
... Luminosity- a star’s ACTUAL brightness. It depends on the size and temperature. *DISTANCE FROM EARTH IS NOT A FACTOR! Absolute magnitude- measure of how bright stars would be if they were the same distance from Earth Example) What if I held a light bulb in front of your face and then walked across ...
... Luminosity- a star’s ACTUAL brightness. It depends on the size and temperature. *DISTANCE FROM EARTH IS NOT A FACTOR! Absolute magnitude- measure of how bright stars would be if they were the same distance from Earth Example) What if I held a light bulb in front of your face and then walked across ...
Lecture 3
... • A blackbody is an ideal emitter that absorbs all incident energy and reradiates the energy. • We can use this to determine the temperatures of stars and planets. ...
... • A blackbody is an ideal emitter that absorbs all incident energy and reradiates the energy. • We can use this to determine the temperatures of stars and planets. ...
B/W
... (plot of Ls vs. Teff ): and Colour–Magnitude Diagram (e.g. plot of V vs. B-V) From diagrams for nearby stars of known distance we deduce: 1. About 90% of stars lie on the main sequence (broad band passing diagonally across the diagram) 2. Two groups are very much more luminous than MS stars (giants ...
... (plot of Ls vs. Teff ): and Colour–Magnitude Diagram (e.g. plot of V vs. B-V) From diagrams for nearby stars of known distance we deduce: 1. About 90% of stars lie on the main sequence (broad band passing diagonally across the diagram) 2. Two groups are very much more luminous than MS stars (giants ...
Chapter 15. The Chandrasekhar Limit, Iron-56 and Core
... cannot get energy from it by either fusion or fission. It is, therefore, useless to the star as a source of energy and once the iron core forms the star has no choice but to continue shrinking its core, releasing gravitational potential energy, and then relying on electron degeneracy to support the ...
... cannot get energy from it by either fusion or fission. It is, therefore, useless to the star as a source of energy and once the iron core forms the star has no choice but to continue shrinking its core, releasing gravitational potential energy, and then relying on electron degeneracy to support the ...
superflares on Sun-like stars
... Many stars show flares similar to solar flares, and often such stellar flares are much more energetic than solar flares. The total energy of a solar flare is typically 1029 –1032 erg. There are much more energetic flares (1033 –1038 erg) in stars, especially in young stars with rapid rotation. These ...
... Many stars show flares similar to solar flares, and often such stellar flares are much more energetic than solar flares. The total energy of a solar flare is typically 1029 –1032 erg. There are much more energetic flares (1033 –1038 erg) in stars, especially in young stars with rapid rotation. These ...
astrophysics - The University of Sydney
... The cycle then repeats itself. Helium is fused to carbon and oxygen in the star’s core, but eventually the core runs out of helium. Fusion stops, and the core resumes its collapse. This heats up the layer of helium just outside the core, which begins fusing in a shell of its own, inside the hydrogen ...
... The cycle then repeats itself. Helium is fused to carbon and oxygen in the star’s core, but eventually the core runs out of helium. Fusion stops, and the core resumes its collapse. This heats up the layer of helium just outside the core, which begins fusing in a shell of its own, inside the hydrogen ...
1 - TeacherWeb
... for billions of years. Why don’t stars in the main sequence either explode right away or become crushed by their own gravity? ...
... for billions of years. Why don’t stars in the main sequence either explode right away or become crushed by their own gravity? ...
Star Systems and Galaxies
... a huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity astronomers classify most galaxies into the following types: spiral elliptical irregular ...
... a huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity astronomers classify most galaxies into the following types: spiral elliptical irregular ...
Evolution and the Big Bang, ET Life Lec. 6, Jan 18, 2002
... Life of a Star • Birth: collapse of gas cloud forms protostar. • Main sequence: center of star becomes hot ...
... Life of a Star • Birth: collapse of gas cloud forms protostar. • Main sequence: center of star becomes hot ...
File
... Small and medium stars become red giants and then _____ ____________. Their outer layers expand to become red giants. Eventually, the outer parts grow bigger still and drift out into space. The blue white hot core is left behind causing a white dwarf. When there is no more energy it become ...
... Small and medium stars become red giants and then _____ ____________. Their outer layers expand to become red giants. Eventually, the outer parts grow bigger still and drift out into space. The blue white hot core is left behind causing a white dwarf. When there is no more energy it become ...
Astronomy Solar System Formation Sun and Stellar Evolution
... 5. List and label the six major layers of the Sun. a. Be able to draw a cross-section of the Sun. 6. Identify major characteristics of each layer and what processes are taking place in each layer. 7. Describe how temperature changes as you move from the core to the corona. 8. Identify and explain ch ...
... 5. List and label the six major layers of the Sun. a. Be able to draw a cross-section of the Sun. 6. Identify major characteristics of each layer and what processes are taking place in each layer. 7. Describe how temperature changes as you move from the core to the corona. 8. Identify and explain ch ...
Powerpoint of lecture 16
... radius • Shell radius ‘wants’ to be constant • But core inside it is contracting • This requires the envelope to expand, to compensate – star becomes a giant ...
... radius • Shell radius ‘wants’ to be constant • But core inside it is contracting • This requires the envelope to expand, to compensate – star becomes a giant ...
Unit 1
... • We can use the star’s color to estimate its surface temperature – If a star emits most strongly in a wavelength (in nm), then its surface temperature (T) is: ...
... • We can use the star’s color to estimate its surface temperature – If a star emits most strongly in a wavelength (in nm), then its surface temperature (T) is: ...
–1– 1. The Salpeter Initial Mass Function The initial mass function is
... the seminal work of Miller & Scalo (1979). This goes in two steps. First, a present day mass function, PDMF or φ(logM) for main sequence stars is found. This is the number of stars per mass per unit area in the galaxy; it is integrated over the ”vertical” dimension of the disk. The PDMF is given by ...
... the seminal work of Miller & Scalo (1979). This goes in two steps. First, a present day mass function, PDMF or φ(logM) for main sequence stars is found. This is the number of stars per mass per unit area in the galaxy; it is integrated over the ”vertical” dimension of the disk. The PDMF is given by ...
Why does the sky move?
... If the waltzer had no roof, the sky overhead would appear to be spinning around a point directly above the car. This area of sky would always be visible to us no matter where the car was on the track. This is the same for the stars around the north star Polaris. Because Polaris is clos ...
... If the waltzer had no roof, the sky overhead would appear to be spinning around a point directly above the car. This area of sky would always be visible to us no matter where the car was on the track. This is the same for the stars around the north star Polaris. Because Polaris is clos ...
l max T = 0.002897755 m K
... Explain: the V=10 star has the same luminosity in just one band as the mbol=10 star has over all wavelengths, so if you include the bands other than V it looks brighter ...
... Explain: the V=10 star has the same luminosity in just one band as the mbol=10 star has over all wavelengths, so if you include the bands other than V it looks brighter ...
Chapter 10- Stars, Galaxies and the Universe
... 35. A galaxy that does not have a regular shape is classified as a(n) ____________________ galaxy. 36. According to the big bang theory, the universe formed about _________________________ years ago. 37. Telescopes work by collecting and focusing different forms of ____________________ radiation. 38 ...
... 35. A galaxy that does not have a regular shape is classified as a(n) ____________________ galaxy. 36. According to the big bang theory, the universe formed about _________________________ years ago. 37. Telescopes work by collecting and focusing different forms of ____________________ radiation. 38 ...
Quiz 3 Feedback Electron Jumps in Atoms Emission and absorption
... it has emission lines, absorption lines, or a continuous spectrum.” •All stars essentially have absorption lines on a thermal (continuous) spectrum. If there are emission lines, those come from low-density hotter gas above the surface. “You get temperature from the mass.” •The mass of a star tells y ...
... it has emission lines, absorption lines, or a continuous spectrum.” •All stars essentially have absorption lines on a thermal (continuous) spectrum. If there are emission lines, those come from low-density hotter gas above the surface. “You get temperature from the mass.” •The mass of a star tells y ...
Sample Final
... a) supernova explosions cause new stars to form, then they evolve and supernova causing further star formation, and so on. b) stars can form all by themselves without help from spiral density waves or supernovae. c) stars always produce planetary systems that can support life. d) stars produce their ...
... a) supernova explosions cause new stars to form, then they evolve and supernova causing further star formation, and so on. b) stars can form all by themselves without help from spiral density waves or supernovae. c) stars always produce planetary systems that can support life. d) stars produce their ...
Stars and The Universe
... itself, its mass collides at its core and bounces back in an explosion called a ____________. As a result of this explosion, parts of the massive star fly away into space, where they can form _____________. If the mass remaining in the dead star’s core is 3 times our sun’s mass, it will form a _____ ...
... itself, its mass collides at its core and bounces back in an explosion called a ____________. As a result of this explosion, parts of the massive star fly away into space, where they can form _____________. If the mass remaining in the dead star’s core is 3 times our sun’s mass, it will form a _____ ...
Space
... 3. To magnify the image produced by the eyepiece 4. To produce an image that is magnified by the eyepiece 5. To split light from stars into different colours. ...
... 3. To magnify the image produced by the eyepiece 4. To produce an image that is magnified by the eyepiece 5. To split light from stars into different colours. ...
Death of Stars with the Mass of 0.3
... only a mass of less than about 1.4 sun masses, the fusion stops after the helium in the core has been burned up. Due to gravitational pressure, the star gets compressed and becomes a white dwarf. The outer layers are pushed away, ionized by the UV-rays of the star and begin to glow as a new planetar ...
... only a mass of less than about 1.4 sun masses, the fusion stops after the helium in the core has been burned up. Due to gravitational pressure, the star gets compressed and becomes a white dwarf. The outer layers are pushed away, ionized by the UV-rays of the star and begin to glow as a new planetar ...
The HLCO Project - High Legh Community Observatory
... The largest known star by volume is KW Sagitari which is a whopping 1500 times the size of our Sun The heaviest known star is R136A1 in the Tarantula Nebula which started life as a lumbering 320 times heavier than the Sun The hottest known stars belongs to a special class known as a ‘Wolf-Rayet’ and ...
... The largest known star by volume is KW Sagitari which is a whopping 1500 times the size of our Sun The heaviest known star is R136A1 in the Tarantula Nebula which started life as a lumbering 320 times heavier than the Sun The hottest known stars belongs to a special class known as a ‘Wolf-Rayet’ and ...
Lecture 24: High Mass Star Formation Astro 6890/8980 Prof. Tom
... photon pressure for high mass stars. ...
... photon pressure for high mass stars. ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.