Astrophysics 12 - Stellar Evolution
... Eventually the temperature at the centre of the protostar reaches a few million degrees and hydrogen nuclei start to fuse together to form helium. ...
... Eventually the temperature at the centre of the protostar reaches a few million degrees and hydrogen nuclei start to fuse together to form helium. ...
Stellar Masses and the Main Sequence
... • The Dynamical Timescale: How long does it take a star’s interior to feel changes and its surface? (For instance, if the star accreted mass, how long would it take the interior to feel the extra weight?) Alternatively, how long does it take an object to “fall” to the star’s ...
... • The Dynamical Timescale: How long does it take a star’s interior to feel changes and its surface? (For instance, if the star accreted mass, how long would it take the interior to feel the extra weight?) Alternatively, how long does it take an object to “fall” to the star’s ...
Space Science Chapter 4 Reading Guide BIG IDEA: Our Sun is
... Which layers are in the Sun’s interior? Which layers are in the Sun’s atmosphere? Why is the photosphere often called the Sun’s surface? Why is the corona NOT normally visible? ...
... Which layers are in the Sun’s interior? Which layers are in the Sun’s atmosphere? Why is the photosphere often called the Sun’s surface? Why is the corona NOT normally visible? ...
The Birth of Stars
... Sometimes (especially in spiral arms), the gas is compressed enough that the dust is thick and gravity can collapse knots in these “molecular” clouds to make new stars. ...
... Sometimes (especially in spiral arms), the gas is compressed enough that the dust is thick and gravity can collapse knots in these “molecular” clouds to make new stars. ...
Lailaigib Lifecycle Of A Star
... stellar cores which nuclear fusion has stopped, and are exposed to space following the loss of the old star's bloated outer envelope, typically as a planetary nebulahttp://www.daviddarling.info/encyclopedi a/W/whitedwarf.html ...
... stellar cores which nuclear fusion has stopped, and are exposed to space following the loss of the old star's bloated outer envelope, typically as a planetary nebulahttp://www.daviddarling.info/encyclopedi a/W/whitedwarf.html ...
Ch.21 Stars, Galaxies, and the Universe Section 3: Lives of Stars
... High-mass stars quickly evolve into brilliant supergiants When a supergiant runs out of fuel, it can explode suddenly The supernovas can become part of a nebula This nebula can then contract to form a new, partly recycled star o Neutron Stars: are the remains of high-mass stars They are ev ...
... High-mass stars quickly evolve into brilliant supergiants When a supergiant runs out of fuel, it can explode suddenly The supernovas can become part of a nebula This nebula can then contract to form a new, partly recycled star o Neutron Stars: are the remains of high-mass stars They are ev ...
Life Cycle of a Star
... White Dwarf • Gravity will cause the red giant to collapse • The sun is now much cooler and it ...
... White Dwarf • Gravity will cause the red giant to collapse • The sun is now much cooler and it ...
Self Assessment: Life Cycle of a Star
... a) the collapse of the iron core of an intermediate mass star b) the collapse of the iron core of a star with a mass greater than about six solar masses c) the collapse of a planetary nebula d) the collapse of the a star's core during the formation of a planetary nebula 4. The length of a star's l ...
... a) the collapse of the iron core of an intermediate mass star b) the collapse of the iron core of a star with a mass greater than about six solar masses c) the collapse of a planetary nebula d) the collapse of the a star's core during the formation of a planetary nebula 4. The length of a star's l ...
Star Factories: Nuclear Fusion and the Creation of the Elements
... The R-Process When the supernova explodes, large numbers of neutrons are shot out of the interior of the star at high velocities. Think of these like pellets in a shot gun shell that has been fired. These neutrons pass through the outer regions of the star, colliding with the atoms already there (m ...
... The R-Process When the supernova explodes, large numbers of neutrons are shot out of the interior of the star at high velocities. Think of these like pellets in a shot gun shell that has been fired. These neutrons pass through the outer regions of the star, colliding with the atoms already there (m ...
Document
... Collapse takes about 3 × 107 yr Magnetic field and rotation (removal of angular momentum, magnetic breaking) Fragmentation (star formation) Accretion of material in 106 yr to form a proto-star (hydrostatic equilibrium, Teff = 3000 K) ...
... Collapse takes about 3 × 107 yr Magnetic field and rotation (removal of angular momentum, magnetic breaking) Fragmentation (star formation) Accretion of material in 106 yr to form a proto-star (hydrostatic equilibrium, Teff = 3000 K) ...
Forging the elements
... Hydrogen burning Stars form with masses between about 1/10 and 100 times the mass of the sun. For most of their lifetimes they burn by the nuclear fusion of hydrogen to helium. Stars with higher masses are more luminous : ...
... Hydrogen burning Stars form with masses between about 1/10 and 100 times the mass of the sun. For most of their lifetimes they burn by the nuclear fusion of hydrogen to helium. Stars with higher masses are more luminous : ...
Astronomy Learning Objectives and Study Questions for Chapter 13
... 5. As a massive star’s degenerate iron core collapses to nuclear density, core bounce creates a shock wave that blows the outer layers of the star apart as a _____. A. magnetar B. nova C. planetary nebula D. Type Ia supernova E. Type II supernova 6. When stars with initial masses between 8 and 25 M ...
... 5. As a massive star’s degenerate iron core collapses to nuclear density, core bounce creates a shock wave that blows the outer layers of the star apart as a _____. A. magnetar B. nova C. planetary nebula D. Type Ia supernova E. Type II supernova 6. When stars with initial masses between 8 and 25 M ...
Ay123 Fall 2011 STELLAR STRUCTURE AND EVOLUTION Problem Set 2
... (3) Stein 2051, M = 0.50 M⊙ or 0.72 M⊙ , R = 0.0115 R⊙ , and try to infer their compositions. e. The results you have derived above should show that as M → 0, R → ∞. Clearly, at some point this result must break down (think about where Jupiter would fall on this plot !). This is because when the den ...
... (3) Stein 2051, M = 0.50 M⊙ or 0.72 M⊙ , R = 0.0115 R⊙ , and try to infer their compositions. e. The results you have derived above should show that as M → 0, R → ∞. Clearly, at some point this result must break down (think about where Jupiter would fall on this plot !). This is because when the den ...
Solution
... 1c) The absorption spectrum of a star is completely determined by its chemical composition alone. True? N [The temperature plays also an important role] 1d) Because hydrogen is the most common element in stars, the Hydrogen Balmer absorption lines are the most prominent (dark) ones for all stars. Tr ...
... 1c) The absorption spectrum of a star is completely determined by its chemical composition alone. True? N [The temperature plays also an important role] 1d) Because hydrogen is the most common element in stars, the Hydrogen Balmer absorption lines are the most prominent (dark) ones for all stars. Tr ...
universe_pp_4 - Cobb Learning
... inward packing it into a smaller space •Gravity is so strong that nothing can escape... ...
... inward packing it into a smaller space •Gravity is so strong that nothing can escape... ...
Main Sequence Stars and their Lifetimes
... 3. Temperature (from stellar spectrum – Blackbody curve) 4. Radius ...
... 3. Temperature (from stellar spectrum – Blackbody curve) 4. Radius ...
Lifecycle of Stars
... 1) Once your teacher has approved each word timeline and you have recorded them on the back of this page, you will create a personal poster that visually displays the four life cycles. You will work in table teams to complete this process, but you will each create your own mini-poster. 2) Use your n ...
... 1) Once your teacher has approved each word timeline and you have recorded them on the back of this page, you will create a personal poster that visually displays the four life cycles. You will work in table teams to complete this process, but you will each create your own mini-poster. 2) Use your n ...
Final Review Questions. 1. Compare the atmospheric scale height of
... 18. Why is it that at T ∼ 107 K, the proton-proton chain and the CNO cycle produce roughly the same amount of energy, even though the CNO cycle requires much higher Gamov energies (and thus has much lower quantum tunneling probabilities)? 19. Why does the central temperature of the Sun increase slig ...
... 18. Why is it that at T ∼ 107 K, the proton-proton chain and the CNO cycle produce roughly the same amount of energy, even though the CNO cycle requires much higher Gamov energies (and thus has much lower quantum tunneling probabilities)? 19. Why does the central temperature of the Sun increase slig ...
The Life Cycles of Stars MEDIUM STARS MASSIVE STARS
... medium size star begins to die. Gravity causes the last of the star's matter to collapse inward and compact. This is the white dwarf stage. At this stage, the star's matter is extremely dense. White dwarfs shine with a white hot light. Once all of their energy is gone, they no longer emit light. The ...
... medium size star begins to die. Gravity causes the last of the star's matter to collapse inward and compact. This is the white dwarf stage. At this stage, the star's matter is extremely dense. White dwarfs shine with a white hot light. Once all of their energy is gone, they no longer emit light. The ...
Stellar evolution
... Some rotate at very high speeds, and are called pulsars. Pulsars have extreme magnetic fields. ...
... Some rotate at very high speeds, and are called pulsars. Pulsars have extreme magnetic fields. ...
Requiem for a Star
... produced by the fusion of light elements into heavier elements •If fuel is exhausted then internal pressure is not maintained, and gravity causes collapse of star ...
... produced by the fusion of light elements into heavier elements •If fuel is exhausted then internal pressure is not maintained, and gravity causes collapse of star ...
STUDY GUIDE FOR CHAPTER 1
... B. Different types of stars are in different regions. You should know what types they are and what regions of the H-R diagram they are found in. 1. Where are the supergiants? 2. Where are the white dwarfs? 3. The main sequence is where most of the stars are. a. What does it look like? b. For stars o ...
... B. Different types of stars are in different regions. You should know what types they are and what regions of the H-R diagram they are found in. 1. Where are the supergiants? 2. Where are the white dwarfs? 3. The main sequence is where most of the stars are. a. What does it look like? b. For stars o ...
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.