Sizes of Stars - The University of Texas at Dallas
... up. When the core is sufficiently dense and hot, fusion begins. The energy released by fusion keeps the star from collapsing much further. The more mass a star has, the hotter the interior of the star will be, and the higher the pressure will be in the core. Hydrogen atoms are more quickly converted ...
... up. When the core is sufficiently dense and hot, fusion begins. The energy released by fusion keeps the star from collapsing much further. The more mass a star has, the hotter the interior of the star will be, and the higher the pressure will be in the core. Hydrogen atoms are more quickly converted ...
Astronomy 110 Announcements: Life and Death of a Low Mass Star
... What happens when the star’s core runs out of helium? A. B. C. D. ...
... What happens when the star’s core runs out of helium? A. B. C. D. ...
Astronomy 101
... The brightest stars are stars of the 1st magnitude. The dimmest stars you can see (with just your eyes) are stars of the 6th magnitude. A star of the 1st magnitude is 100x brighter than a star of the 6th magnitude Thus a star of the 2nd magnitude is 2.512 dimmer than a 1st mag star. ...
... The brightest stars are stars of the 1st magnitude. The dimmest stars you can see (with just your eyes) are stars of the 6th magnitude. A star of the 1st magnitude is 100x brighter than a star of the 6th magnitude Thus a star of the 2nd magnitude is 2.512 dimmer than a 1st mag star. ...
JeopardyCh21StarsGalaxiesUniverse
... Lives of Stars for 1200 The life cycle of a star begins with __________________ which is the joining of atoms of hydrogen to form helium. ...
... Lives of Stars for 1200 The life cycle of a star begins with __________________ which is the joining of atoms of hydrogen to form helium. ...
Chapter 21 Jeopardy
... Lives of Stars for 1200 The life cycle of a star begins with __________________ which is the joining of atoms of hydrogen to form helium. ...
... Lives of Stars for 1200 The life cycle of a star begins with __________________ which is the joining of atoms of hydrogen to form helium. ...
The Story of Pulsational Pair-Instability SNe
... Do pair instability ejections have to be the mechanism by which the envelope is removed? It seems like any stellar wind followed by any explosion would lead to high speed collisions of gas. What is special about the pair instability ejections that make them more likely than other scenarios? Last wee ...
... Do pair instability ejections have to be the mechanism by which the envelope is removed? It seems like any stellar wind followed by any explosion would lead to high speed collisions of gas. What is special about the pair instability ejections that make them more likely than other scenarios? Last wee ...
Signatures of the first stars in the 21cm Emission and Absorption
... • Central gas cools only to T ≈ 200 K. Molecular hydrogen lines can be collisionally deexcited at density n > 104 cm-3, making the cooling rate independent of density and inhibiting fragmentation. • Jeans mass ≈ 300 Msun . • Accretion rate ≈ cs3/G ≈ 10-3 Msun/yr • The first metal-free stars were mas ...
... • Central gas cools only to T ≈ 200 K. Molecular hydrogen lines can be collisionally deexcited at density n > 104 cm-3, making the cooling rate independent of density and inhibiting fragmentation. • Jeans mass ≈ 300 Msun . • Accretion rate ≈ cs3/G ≈ 10-3 Msun/yr • The first metal-free stars were mas ...
Contents and structure of the Milky Way I
... Magnitudes are often given in a particular bandpass; this is because we measure the brightness of a star in a particular wavelength range corresponding to the filter on our telescope, not its total luminosity at all wavelengths (the total luminosity is known as bolometric luminosity). Some common fi ...
... Magnitudes are often given in a particular bandpass; this is because we measure the brightness of a star in a particular wavelength range corresponding to the filter on our telescope, not its total luminosity at all wavelengths (the total luminosity is known as bolometric luminosity). Some common fi ...
Stars, Galaxies, and the Universe
... After the big bang, matter in the universe separated into galaxies. Gas and dust spread throughout space in our galaxy. About 5 billion years ago, a giant cloud of gas and dust, or nebula, collapsed to form the solar system. Nebula shrank to form a disk = the sun was born. The spheres closest to the ...
... After the big bang, matter in the universe separated into galaxies. Gas and dust spread throughout space in our galaxy. About 5 billion years ago, a giant cloud of gas and dust, or nebula, collapsed to form the solar system. Nebula shrank to form a disk = the sun was born. The spheres closest to the ...
Astronomy Exam #2 for the 10
... These brightest stars are a hundreds of times more luminous if not more and will therefore have lifetimes hundreds of times shorter than the Suns – or less than 10 million years. The giant stars have even less time to live since they are already in the last few percent of their lifetime. The tempera ...
... These brightest stars are a hundreds of times more luminous if not more and will therefore have lifetimes hundreds of times shorter than the Suns – or less than 10 million years. The giant stars have even less time to live since they are already in the last few percent of their lifetime. The tempera ...
PHY-105: Final Stages of Stellar Evolution
... saw that this fraction is about 8%. What consequently happens to the star depends critically on mass, but we’ll look at typical cases. When the SC limit is reached, core begins to collapse causing evolution to occur on a much faster timescale. The core collapse releases gravitational potential energ ...
... saw that this fraction is about 8%. What consequently happens to the star depends critically on mass, but we’ll look at typical cases. When the SC limit is reached, core begins to collapse causing evolution to occur on a much faster timescale. The core collapse releases gravitational potential energ ...
Axions and White Dwarfs
... mass of the parent star (for convenience all white dwarfs are labeled with the mass of the main sequence progenitor), tcool is the cooling time down to luminosity l, τcool = dt/dMbol is the characteristic cooling time, Ms and Mi are the maximum and the minimum masses of the main sequence stars able ...
... mass of the parent star (for convenience all white dwarfs are labeled with the mass of the main sequence progenitor), tcool is the cooling time down to luminosity l, τcool = dt/dMbol is the characteristic cooling time, Ms and Mi are the maximum and the minimum masses of the main sequence stars able ...
Red giants aren`t just big, they`re turbulent
... hydrogen contentedly for millions to billions of years, depending on their masses. Large stars burn hotter and more quickly than do smaller stars. The Sun, an average star estimated to be at the midpoint in its life, is 5 billion years old. In another 2 to 5 billion years, it will have exhausted its ...
... hydrogen contentedly for millions to billions of years, depending on their masses. Large stars burn hotter and more quickly than do smaller stars. The Sun, an average star estimated to be at the midpoint in its life, is 5 billion years old. In another 2 to 5 billion years, it will have exhausted its ...
Dark Matter
... [The video and article state that stars with masses between 1.4 and 3.2 MSun can become neutron stars. Technically, that range refers to the mass leftover in a remnant of a supernova explosion. In class we have said that stars that were born with more than 8 MSun will explode as supernovae leaving b ...
... [The video and article state that stars with masses between 1.4 and 3.2 MSun can become neutron stars. Technically, that range refers to the mass leftover in a remnant of a supernova explosion. In class we have said that stars that were born with more than 8 MSun will explode as supernovae leaving b ...
l13
... All types of SNe apart from Type Ia are not observed in old stellar populations (such as elliptical galaxies). In particular Type II are observed mostly in the gas and dust rich arms of spiral galaxies. Star formation is ongoing and young stars are abundant. By contrast Type Ia SNe are found in all ...
... All types of SNe apart from Type Ia are not observed in old stellar populations (such as elliptical galaxies). In particular Type II are observed mostly in the gas and dust rich arms of spiral galaxies. Star formation is ongoing and young stars are abundant. By contrast Type Ia SNe are found in all ...
Chapter 10 - Croydon Music and Arts
... Croydon Music Stars – Teachers Actions (to be read in conjunction with the Croydon Music Stars handbook) Croydon Music Stars are used with all primary pupils learning with CMA. Teachers may use them for secondary age pupils as seems appropriate. For SoundStart pupils, the lead teacher should keep an ...
... Croydon Music Stars – Teachers Actions (to be read in conjunction with the Croydon Music Stars handbook) Croydon Music Stars are used with all primary pupils learning with CMA. Teachers may use them for secondary age pupils as seems appropriate. For SoundStart pupils, the lead teacher should keep an ...
STARS: how they are born, live and die
... about the size of Earth. Its weight supported against further collapse by electron degeneracy pressure, it will do nothing but sit there and cool off, for eternity. ...
... about the size of Earth. Its weight supported against further collapse by electron degeneracy pressure, it will do nothing but sit there and cool off, for eternity. ...
My Presentation
... Deep inside, a gas called hydrogen is changed into gas called helium. As it changes, it gives off energy. The star then gets very hot and gives off light. Stars have different temperatures and sizes. As a result, some stars are brighter than others, and they have different colors. Some stars look ye ...
... Deep inside, a gas called hydrogen is changed into gas called helium. As it changes, it gives off energy. The star then gets very hot and gives off light. Stars have different temperatures and sizes. As a result, some stars are brighter than others, and they have different colors. Some stars look ye ...
Microsoft Word - LifeCycleInteractive
... 4: _______________; 5: __________to ___________; 6: _____________ 5. Why does a brown dwarf form? ...
... 4: _______________; 5: __________to ___________; 6: _____________ 5. Why does a brown dwarf form? ...
Module Outlines
... Imagine moving all of the stars in the sky so that they reside on a sphere of radius 10 parsecs that is centered on the Earth. The apparent magnitude that these stars would have at that time is their absolute magnitude. Thus, it is a theoretical quantity. ...
... Imagine moving all of the stars in the sky so that they reside on a sphere of radius 10 parsecs that is centered on the Earth. The apparent magnitude that these stars would have at that time is their absolute magnitude. Thus, it is a theoretical quantity. ...
Document
... • protostellar core forms [~ 5 AU] with free-falling gas above • dust vaporizes as T increases • convective period ...
... • protostellar core forms [~ 5 AU] with free-falling gas above • dust vaporizes as T increases • convective period ...
The Mass of the Galaxy - University of California, Berkeley
... Having the spins aligned is a higher energy state. So in about 10 million years it will decay to the ground state (anti-aligned). Or a 21-cm photon can be absorbed and align the spins. Because the Galaxy is transparent, it is hard to tell where the emission is coming from along the line-of-sight. Bu ...
... Having the spins aligned is a higher energy state. So in about 10 million years it will decay to the ground state (anti-aligned). Or a 21-cm photon can be absorbed and align the spins. Because the Galaxy is transparent, it is hard to tell where the emission is coming from along the line-of-sight. Bu ...
RED DWARFS AND THE END OF THE MAIN SEQUENCE
... temperature cannot increase because of the sharply increasing opacity with increasing temperature, i.e., the photosphere encounters an opacity wall. As a result, the photospheric temperature remains (nearly) constant and the star ascends the red giant branch. For stars with photospheres that do not ...
... temperature cannot increase because of the sharply increasing opacity with increasing temperature, i.e., the photosphere encounters an opacity wall. As a result, the photospheric temperature remains (nearly) constant and the star ascends the red giant branch. For stars with photospheres that do not ...
Lecture 16
... In order to accurately model the interior of a star, we need many more equations, describing temperature, pressure, energy flow, etc. Solving all these equations is not easy but can be done numerically. However, we can easily get a rough estimate of the pressure at the centre of a star by making som ...
... In order to accurately model the interior of a star, we need many more equations, describing temperature, pressure, energy flow, etc. Solving all these equations is not easy but can be done numerically. However, we can easily get a rough estimate of the pressure at the centre of a star by making som ...
The Star–Gas–Star Cycle
... • older generation of stars • contains no gas or dust • location of the globular clusters ...
... • older generation of stars • contains no gas or dust • location of the globular clusters ...
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.