iptfsummer2014bildsten
... • Secular stability requires that the donor star stay within the Roche radius as mass is lost. • If not stable, then likely some excitement. . ...
... • Secular stability requires that the donor star stay within the Roche radius as mass is lost. • If not stable, then likely some excitement. . ...
Neutron Stars and Black Holes
... a)! They are only regular pulsing stars, so it is a natural evolution of stars with magnetic fields. b)! Supernova of a massive star, leaving a neutron core mass of 1.4 to 3 solar masses. c)! By evolution from a supergiant to a compact, hot, but pulsing star. d)! Through the evolution of a binary sy ...
... a)! They are only regular pulsing stars, so it is a natural evolution of stars with magnetic fields. b)! Supernova of a massive star, leaving a neutron core mass of 1.4 to 3 solar masses. c)! By evolution from a supergiant to a compact, hot, but pulsing star. d)! Through the evolution of a binary sy ...
Discussion Activity #13
... A. The total amount of gas will be about the same, but it will contain a much higher percentage of elements heavier than hydrogen and helium. B. Thanks to the recycling of the star-gas-star cycle, the interstellar medium should look about the same in 50 billion years as it does today. C. The total a ...
... A. The total amount of gas will be about the same, but it will contain a much higher percentage of elements heavier than hydrogen and helium. B. Thanks to the recycling of the star-gas-star cycle, the interstellar medium should look about the same in 50 billion years as it does today. C. The total a ...
AN INTRODUCTION TO ASTRONOMY Dr. Uri Griv Department of Physics, Ben-Gurion University
... stars → random velocities → no rotation • The thermodynamic Maxwell–Boltzmann (MB) distribution of velocities ...
... stars → random velocities → no rotation • The thermodynamic Maxwell–Boltzmann (MB) distribution of velocities ...
Chapter 21 Stellar Explosions
... Iron-56 is the most stable nucleus, so it neither fuses nor decays. ...
... Iron-56 is the most stable nucleus, so it neither fuses nor decays. ...
![Chapter Zero Section 0.2 [reprint from Jesperson 7th] Supernovas](http://s1.studyres.com/store/data/009810478_1-e5fd9db32afbb84e749a32319c4308af-300x300.png)
Chapter Zero Section 0.2 [reprint from Jesperson 7th] Supernovas
... Continuing, the carbon nuclei entered into nuclear reactions that produced argon. As the amount of argon increased, it migrated inward and became the core, now surrounded by a layer rich in carbon, then a helium layer and finally the outer hydrogen layer. We now have a pattern: Each successively hea ...
... Continuing, the carbon nuclei entered into nuclear reactions that produced argon. As the amount of argon increased, it migrated inward and became the core, now surrounded by a layer rich in carbon, then a helium layer and finally the outer hydrogen layer. We now have a pattern: Each successively hea ...
STARS IN HYDROSTATIC EQUILIBRIUM Gravitational energy and
... The non-relativistic case is equivalent to the well known virial theorem. The ultra-relativistic results is somewhat paradoxical, with the total energy of a star being zero. This result is only approximate, as it relates to the case when all particles within the star are moving with the speed of lig ...
... The non-relativistic case is equivalent to the well known virial theorem. The ultra-relativistic results is somewhat paradoxical, with the total energy of a star being zero. This result is only approximate, as it relates to the case when all particles within the star are moving with the speed of lig ...
ppt - Department of Physics & Astronomy at the University of Utah
... Carbon features in spectra ...
... Carbon features in spectra ...
minnesota
... At 408 ms, KE = 0.42 foe, stored dissociation energy is 0.38 foe, and the total explosion energy is still growing at 4.4 foe/s ...
... At 408 ms, KE = 0.42 foe, stored dissociation energy is 0.38 foe, and the total explosion energy is still growing at 4.4 foe/s ...
Lecture 2
... Stars are held together by gravitation – attraction exerted on each part of the star by all other parts Collapse is resisted by internal thermal pressure. These two forces play the principal role in determining stellar structure – they must be (at least almost) in balance Thermal properties of stars ...
... Stars are held together by gravitation – attraction exerted on each part of the star by all other parts Collapse is resisted by internal thermal pressure. These two forces play the principal role in determining stellar structure – they must be (at least almost) in balance Thermal properties of stars ...
MSci Astrophysics 210PHY412 - QUB Astrophysics Research Centre
... For our stars – which are isolated, static, and spherically symmetric – there are four basic equations to describe structure. All physical quantities depend on the distance from the centre of the star alone 1) Equation of hydrostatic equilibrium: at each radius, forces due to pressure differences b ...
... For our stars – which are isolated, static, and spherically symmetric – there are four basic equations to describe structure. All physical quantities depend on the distance from the centre of the star alone 1) Equation of hydrostatic equilibrium: at each radius, forces due to pressure differences b ...
Document
... • The luminosity of a star represents the amount of energy emitted per second. There must be a source of this energy, and it cannot last forever. • The amount of “fuel” a star has is proportional to its initial mass. • The length of time the fuel can be spent is equal to the amount of fuel divided b ...
... • The luminosity of a star represents the amount of energy emitted per second. There must be a source of this energy, and it cannot last forever. • The amount of “fuel” a star has is proportional to its initial mass. • The length of time the fuel can be spent is equal to the amount of fuel divided b ...
5 log5 − = − d . N
... Orbital measurements of the binary system can give M, and thus R from the mass-radius relationship. If the disc can be resolved, Rd can be determined, thus allowing us to calculate m& from measurements of LAcc. Novae: Accretion transfers H on to the white dwarf. This mass ‘piles up’ on the surface, ...
... Orbital measurements of the binary system can give M, and thus R from the mass-radius relationship. If the disc can be resolved, Rd can be determined, thus allowing us to calculate m& from measurements of LAcc. Novae: Accretion transfers H on to the white dwarf. This mass ‘piles up’ on the surface, ...
Star G has an apparent magnitude of +5.0 and an absolute
... • All galaxies may become active more than once in their lifetime • All galaxies go through an active phase, and fewer galaxies in the past were active than now • Some galaxies go through an active phase, and more galaxies in the past were active than now • Most galaxies never become active in their ...
... • All galaxies may become active more than once in their lifetime • All galaxies go through an active phase, and fewer galaxies in the past were active than now • Some galaxies go through an active phase, and more galaxies in the past were active than now • Most galaxies never become active in their ...
Document
... distance of one of the objects from the other cubed. This is a simple problem that only works if you do the following: P must be in earth years, and amust be in au. An au is the distance from the earth to the Sun (93 million miles). Mars is 1.5 au , and Jupiter is 5 au. So lets use the formula on th ...
... distance of one of the objects from the other cubed. This is a simple problem that only works if you do the following: P must be in earth years, and amust be in au. An au is the distance from the earth to the Sun (93 million miles). Mars is 1.5 au , and Jupiter is 5 au. So lets use the formula on th ...
Goal: To understand the HR diagram
... • If we plotted all the stars from a single cluster what might we get? • First we should ask 2 questions: • 1) How do the distances from us compare to all the stars in the cluster (close to same, or not close)? • 2) How do the ages of the stars in the cluster compare? ...
... • If we plotted all the stars from a single cluster what might we get? • First we should ask 2 questions: • 1) How do the distances from us compare to all the stars in the cluster (close to same, or not close)? • 2) How do the ages of the stars in the cluster compare? ...
L2 - QUB Astrophysics Research Centre
... For our stars – which are isolated, static, and spherically symmetric – there are four basic equations to describe structure. All physical quantities depend on the distance from the centre of the star alone 1) Equation of hydrostatic equilibrium: at each radius, forces due to pressure differences b ...
... For our stars – which are isolated, static, and spherically symmetric – there are four basic equations to describe structure. All physical quantities depend on the distance from the centre of the star alone 1) Equation of hydrostatic equilibrium: at each radius, forces due to pressure differences b ...
The structure and evolution of stars
... For our stars – which are isolated, static, and spherically symmetric – there are four basic equations to describe structure. All physical quantities depend on the distance from the centre of the star alone 1) Equation of hydrostatic equilibrium: at each radius, forces due to pressure differences ...
... For our stars – which are isolated, static, and spherically symmetric – there are four basic equations to describe structure. All physical quantities depend on the distance from the centre of the star alone 1) Equation of hydrostatic equilibrium: at each radius, forces due to pressure differences ...
When Stars Go Boom
... the Sun is one such star. Because we do not see obvious changes in stars on timescales of days or even years, most students don’t give much thought to the question of how long stars last, and what happens to them when they stop shining. “When Stars Go Boom!” introduces several key ideas about stars, ...
... the Sun is one such star. Because we do not see obvious changes in stars on timescales of days or even years, most students don’t give much thought to the question of how long stars last, and what happens to them when they stop shining. “When Stars Go Boom!” introduces several key ideas about stars, ...
The Interstellar Medium (ISM)
... H-R diagram for a young open cluster shows pre-Main Sequence stars ...
... H-R diagram for a young open cluster shows pre-Main Sequence stars ...
$doc.title
... • They are ubiquitous, even though only a small fraction are active today; but these SMBHs are just dormant quasars, which were once active - this is where their mass comes from! • They are detected through kinematics of stars or gas near the galactic centers: These are test particles probing the ...
... • They are ubiquitous, even though only a small fraction are active today; but these SMBHs are just dormant quasars, which were once active - this is where their mass comes from! • They are detected through kinematics of stars or gas near the galactic centers: These are test particles probing the ...
Hydrostatic Equilibrium of Hypothetical Quark Stars
... Department of Physics, Kyoto University Kyoto ...
... Department of Physics, Kyoto University Kyoto ...
Measuring the Frequency of Massive Planets around M
... (0.4 MSun), the planet is 2.4 times the mass of Jupiter. ...
... (0.4 MSun), the planet is 2.4 times the mass of Jupiter. ...
The Evolution and Explosion of Massive Stars
... rotation and magnetic fields?), a shock wave moves out through the star ejecting everything external to the neutron star. In some cases – quite massive stars – the ejection may be inefficient, and matter may fall back forming a black hole. In some cases the outgoing shock may never form. When succes ...
... rotation and magnetic fields?), a shock wave moves out through the star ejecting everything external to the neutron star. In some cases – quite massive stars – the ejection may be inefficient, and matter may fall back forming a black hole. In some cases the outgoing shock may never form. When succes ...
L3 - QUB Astrophysics Research Centre
... Minimum mean temperature of a star We have seen that pressure, P, is an important term in the equation of hydrostatic equilibrium and the Virial theorem. We have derived a minimum value for the central pressure (Pc>4.5 108 atmospheres) What physical processes give rise to this pressure – which ar ...
... Minimum mean temperature of a star We have seen that pressure, P, is an important term in the equation of hydrostatic equilibrium and the Virial theorem. We have derived a minimum value for the central pressure (Pc>4.5 108 atmospheres) What physical processes give rise to this pressure – which ar ...
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.