Slide 1 - cosmos.esa.int
... detectable beyond the Virgo cluster (by IceCube or Dusel). • But the most likely detection is through the diffuse neutrino background. If they occur at low redshift, they will fit directly in the GADZOOKS energy band. ...
... detectable beyond the Virgo cluster (by IceCube or Dusel). • But the most likely detection is through the diffuse neutrino background. If they occur at low redshift, they will fit directly in the GADZOOKS energy band. ...
ASTRONOMY 0089: EXAM 2 Class Meets M,W,F, 1:00 PM Mar 22
... d. Its energy will be generated via the fusion of He into C in its inner core. e. It will have a surface temperature of around 3500K and hence, from the Stefan Boltzmann law, it follows that its Luminosity will be lower than the present Luminosity of the Sun. 18. In the H-R diagram, low mass main se ...
... d. Its energy will be generated via the fusion of He into C in its inner core. e. It will have a surface temperature of around 3500K and hence, from the Stefan Boltzmann law, it follows that its Luminosity will be lower than the present Luminosity of the Sun. 18. In the H-R diagram, low mass main se ...
protostars and pre-main
... get piled onto the top. Luminosity is generated at the surface by accretion shocka ...
... get piled onto the top. Luminosity is generated at the surface by accretion shocka ...
File - Physical Science
... Nuclear Fusion and Nucleosynthesis Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by tremendous atomic collisions that alter the atomic structure and release an enormous amount of energy. This makes stars hot and bright. Nuclear fusion is an atomic reaction that fuel ...
... Nuclear Fusion and Nucleosynthesis Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by tremendous atomic collisions that alter the atomic structure and release an enormous amount of energy. This makes stars hot and bright. Nuclear fusion is an atomic reaction that fuel ...
Stellar structure
... The star will be convectively unstable in regions where dlnT/dlnP > (g – 1)/g, where (g-1)/g is the temp. gradient expected in an adiabatic gas (4/3 < g < 5/3) depending on degrees of freedom f of atoms/molecules/ions, g = ((f+2)/f) The conditions of the gas in the star will not be adiabatic in gene ...
... The star will be convectively unstable in regions where dlnT/dlnP > (g – 1)/g, where (g-1)/g is the temp. gradient expected in an adiabatic gas (4/3 < g < 5/3) depending on degrees of freedom f of atoms/molecules/ions, g = ((f+2)/f) The conditions of the gas in the star will not be adiabatic in gene ...
Evolution of High Mass Stars
... Massive stars will have very different evolutionary endpoints (remnants: neutron star or black hole vs white dwarf) ...
... Massive stars will have very different evolutionary endpoints (remnants: neutron star or black hole vs white dwarf) ...
Monday, Oct. 20
... When helium fusion starts generating energy in the core of a red giant, the core expands and hydrogen fusion in the shell around the core slows down. As a result, less total energy is being generated, and the envelope contracts and warms up some. But pretty soon all of the helium in the core is conv ...
... When helium fusion starts generating energy in the core of a red giant, the core expands and hydrogen fusion in the shell around the core slows down. As a result, less total energy is being generated, and the envelope contracts and warms up some. But pretty soon all of the helium in the core is conv ...
The Population of Stars
... The spectra of stars reveal their chemical compositions as well as surface temperatures • Stars are classified into spectral types (subdivisions of the spectral classes O, B, A, F, G, K, and M), based on the major patterns of spectral lines in their spectra ...
... The spectra of stars reveal their chemical compositions as well as surface temperatures • Stars are classified into spectral types (subdivisions of the spectral classes O, B, A, F, G, K, and M), based on the major patterns of spectral lines in their spectra ...
Folie 1
... • R increases more surface more L can be emitted again TE • R increases T decreases at some point opacity increases NO TE star becomes red giant (Hertzsprung-gap!) • Runaway stops at Hayashi-track ...
... • R increases more surface more L can be emitted again TE • R increases T decreases at some point opacity increases NO TE star becomes red giant (Hertzsprung-gap!) • Runaway stops at Hayashi-track ...
Stellar Structure, Polytropes, Standard Stellar Model
... decreases Ye. For a 56Fe white dwarf, the zero-temperature Chandrasekhar mass is only 1.17 M⊙. As the cores of massive stars evolve, there is a general tendency for “core convergence” to occur, i.e., the evolved cores of all massive stars, regardless of mass, tend to be nearly Mch. We see that this ...
... decreases Ye. For a 56Fe white dwarf, the zero-temperature Chandrasekhar mass is only 1.17 M⊙. As the cores of massive stars evolve, there is a general tendency for “core convergence” to occur, i.e., the evolved cores of all massive stars, regardless of mass, tend to be nearly Mch. We see that this ...
大爆炸---宇宙的起源
... body thermal energy coming from all parts of the sky. The radiation is isotropic to roughly one part in 100,000. As the universe expanded, adiabatic cooling caused the plasma to lose energy until it became favorable for electrons to combine with protons, forming hydrogen atoms. This recombination ev ...
... body thermal energy coming from all parts of the sky. The radiation is isotropic to roughly one part in 100,000. As the universe expanded, adiabatic cooling caused the plasma to lose energy until it became favorable for electrons to combine with protons, forming hydrogen atoms. This recombination ev ...
main-sequence stars
... red coloring (for example, Betelgeuse). Hotter temperatures change the color to orange, then yellow (our sun, at about 5500° C), and then white. The hottest stars (such as Sirius) have a bluish white color (above 9500° C). ...
... red coloring (for example, Betelgeuse). Hotter temperatures change the color to orange, then yellow (our sun, at about 5500° C), and then white. The hottest stars (such as Sirius) have a bluish white color (above 9500° C). ...
Astro 10: Introductory Astronomy
... Grading • 6 mult. choice quizzes based on my lectures, with help from the textbook. - ~10 questions each - closed notes • ~2 video quizzes; after seeing ~45 min video program. Take notes and use them for your mult. choice quiz, about 20 questions each • Final Exam: 50 mult. choice questions. You ma ...
... Grading • 6 mult. choice quizzes based on my lectures, with help from the textbook. - ~10 questions each - closed notes • ~2 video quizzes; after seeing ~45 min video program. Take notes and use them for your mult. choice quiz, about 20 questions each • Final Exam: 50 mult. choice questions. You ma ...
Document
... inward gravitational collapse is: a. Halted by degeneracy pressure in the core. b. Halted when the atoms are pushed up against one another and contraction stops. c. Finally balanced by outward thermal pressure from nuclear reactions. d. Finally balanced by radiation emitted in the photosphere. e. no ...
... inward gravitational collapse is: a. Halted by degeneracy pressure in the core. b. Halted when the atoms are pushed up against one another and contraction stops. c. Finally balanced by outward thermal pressure from nuclear reactions. d. Finally balanced by radiation emitted in the photosphere. e. no ...
How big is the Universe?
... 1 light-second ≈ 0.002 AU 1 light-year = 9.461×1015 m≈ 63,241 AU 1 parsec = 30.857×1015 m ≈ 206,265 AU ...
... 1 light-second ≈ 0.002 AU 1 light-year = 9.461×1015 m≈ 63,241 AU 1 parsec = 30.857×1015 m ≈ 206,265 AU ...
Our Place in the Universe: Sizing up the Heavens
... Stellar parallax allows distance to the stars to be determined. Parallax only measurable at distances < several thousand light years. ...
... Stellar parallax allows distance to the stars to be determined. Parallax only measurable at distances < several thousand light years. ...
Integrative Studies 410 Our Place in the Universe
... Small, rapidly rotating objects Can’t be white dwarfs; must be neutron stars ...
... Small, rapidly rotating objects Can’t be white dwarfs; must be neutron stars ...
大爆炸---宇宙的起源 - 中正大學化學系
... body thermal energy coming from all parts of the sky. The radiation is isotropic to roughly one part in 100,000. As the universe expanded, adiabatic cooling caused the plasma to lose energy until it became favorable for electrons to combine with protons, forming hydrogen atoms. This recombination ev ...
... body thermal energy coming from all parts of the sky. The radiation is isotropic to roughly one part in 100,000. As the universe expanded, adiabatic cooling caused the plasma to lose energy until it became favorable for electrons to combine with protons, forming hydrogen atoms. This recombination ev ...
Stellar Notes
... details can you come up with for a Stellar Nursery, or better known as a Nebula? ...
... details can you come up with for a Stellar Nursery, or better known as a Nebula? ...
unit notes filled out
... it capture stars in different stages of development and astronomers were able to piece together the life history of a star using the current laws of physics. Where are stars born? A stars life begins in the inter-stellar medium (space between stars) as a cloud of gas and dust (nebula) What is th ...
... it capture stars in different stages of development and astronomers were able to piece together the life history of a star using the current laws of physics. Where are stars born? A stars life begins in the inter-stellar medium (space between stars) as a cloud of gas and dust (nebula) What is th ...
binary stars
... • As the energy leaks out, the central temperature of the Sun drops. • Lower temperature means lower gas pressure. • The lower gas pressure cannot hold up against gravity – the Sun shrinks. • The added compression puts the Sun’s center under greater pressure, so the central temperature increase ...
... • As the energy leaks out, the central temperature of the Sun drops. • Lower temperature means lower gas pressure. • The lower gas pressure cannot hold up against gravity – the Sun shrinks. • The added compression puts the Sun’s center under greater pressure, so the central temperature increase ...
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.