White dwarf with almost pure oxygen atmosphere
... the core pushing the lighter ones, such as helium provide a critical link to some types of supernovae discovered over the past decade. As relatively Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint pinprick of light to the l ...
... the core pushing the lighter ones, such as helium provide a critical link to some types of supernovae discovered over the past decade. As relatively Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint pinprick of light to the l ...
Birth, Lives, and Death of Stars
... Neutron stars are about 30 kilometers across, so their densities are much larger than even the incredible densities of white dwarfs: 2 x 1014 times the density of water. Recently, the Hubble Space Telescope was able to image one of these very small objects. Even though it is over 660,000 K, the neut ...
... Neutron stars are about 30 kilometers across, so their densities are much larger than even the incredible densities of white dwarfs: 2 x 1014 times the density of water. Recently, the Hubble Space Telescope was able to image one of these very small objects. Even though it is over 660,000 K, the neut ...
Chapter 7 Neutron Stars - Ira-Inaf
... mass cut, which determines the relative fractions of collapses producing a neutron star and a black hole, respectively. The above discussion is summarized in Figure 1, taken from Weinberg, showing the white dwarf and neutron star mass trajectories for the ideal equations of state we considered, as w ...
... mass cut, which determines the relative fractions of collapses producing a neutron star and a black hole, respectively. The above discussion is summarized in Figure 1, taken from Weinberg, showing the white dwarf and neutron star mass trajectories for the ideal equations of state we considered, as w ...
STScI 2005
... • Stars with M>150 M can only be observed in clusters with total stellar mass >104 M. • This requirement limits the potential sample of stellar clusters that can constrain the upper mass limit to only a few in the Galaxy. ...
... • Stars with M>150 M can only be observed in clusters with total stellar mass >104 M. • This requirement limits the potential sample of stellar clusters that can constrain the upper mass limit to only a few in the Galaxy. ...
Astronomy Activity word document
... 13. A protostar is the first step in becoming a ________________________________. 14. After the star finished the protostar phase, it becomes even ________________________. The heavy elements move to the center of the star while the light gases stay in the star's atmosphere. Those gases are usually ...
... 13. A protostar is the first step in becoming a ________________________________. 14. After the star finished the protostar phase, it becomes even ________________________. The heavy elements move to the center of the star while the light gases stay in the star's atmosphere. Those gases are usually ...
August 29 - Astronomy
... The expanding shock wave of a supernova explosion, can cause a nearby cloud of gas to collapse and form new stars. Thus, its heavy nuclei get incorporated into the next generation of stars. ...
... The expanding shock wave of a supernova explosion, can cause a nearby cloud of gas to collapse and form new stars. Thus, its heavy nuclei get incorporated into the next generation of stars. ...
Home | STA Notes
... An HR diagram is really a snapshot of many stars at different stages in their lives. (The process of change that occurs throughout a star's life is known as stellar evolution.) The reason there are so many stars on the main sequence is that stars spend most of their lives there. They start their liv ...
... An HR diagram is really a snapshot of many stars at different stages in their lives. (The process of change that occurs throughout a star's life is known as stellar evolution.) The reason there are so many stars on the main sequence is that stars spend most of their lives there. They start their liv ...
Lecture 18
... • Dying stars expel gas and new elements, producing hot bubbles (~106 K). • Hot gas cools, allowing atomic hydrogen clouds to form (~100–10,000 K). • Further cooling permits molecules to form, making molecular clouds (~30 K). • Gravity forms new stars (and planets) in molecular clouds. ...
... • Dying stars expel gas and new elements, producing hot bubbles (~106 K). • Hot gas cools, allowing atomic hydrogen clouds to form (~100–10,000 K). • Further cooling permits molecules to form, making molecular clouds (~30 K). • Gravity forms new stars (and planets) in molecular clouds. ...
Ch. 21
... the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students exc ...
... the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students exc ...
Back ground information
... process of fusion in which two hydrogen atoms are combined to form a helium atom, and large amounts of energy are released during the process. Some of the energy generated by the star is in the form of light. The size and composition of a star determine the amount of gravity (more mass generates mor ...
... process of fusion in which two hydrogen atoms are combined to form a helium atom, and large amounts of energy are released during the process. Some of the energy generated by the star is in the form of light. The size and composition of a star determine the amount of gravity (more mass generates mor ...
- Lorentz Center
... • White Dwarfs have lots of fuel (He/C/O) and gravitational binding energies per gram less than that of nuclear burning: 1 MeV per baryon ...
... • White Dwarfs have lots of fuel (He/C/O) and gravitational binding energies per gram less than that of nuclear burning: 1 MeV per baryon ...
Lesson 3 - The DK Foundation
... So what is the purpose of identifying these three things: the Star to Guide Us, the Star to Befriend Us and the Constellation to Hold Us? Essentially, it is to give us focal points in the stellar world in order to benefit from the clarity and energy that this contact can give us, and over time to bu ...
... So what is the purpose of identifying these three things: the Star to Guide Us, the Star to Befriend Us and the Constellation to Hold Us? Essentially, it is to give us focal points in the stellar world in order to benefit from the clarity and energy that this contact can give us, and over time to bu ...
ring - The Evergreen State College
... Many stars - including the sun - have magnetic fields, and many - including the sun - ring with sound waves. Why do stars ring? What, if anything, do magnetic fields have to do with the ringing? What light does this shed on the lives of stars and life on Earth? ...
... Many stars - including the sun - have magnetic fields, and many - including the sun - ring with sound waves. Why do stars ring? What, if anything, do magnetic fields have to do with the ringing? What light does this shed on the lives of stars and life on Earth? ...
1. Basic Properties of Stars
... G, K and M. Note that the spectra classes are also divisions of temperature such that O stars are hot, M stars are cool. Between the classes there were 10 subdivisions numbered 0 to 9. For example, our Sun is a G2 star. Sirius, a hot blue star, is type B3. Why do some stars have strong lines of hydr ...
... G, K and M. Note that the spectra classes are also divisions of temperature such that O stars are hot, M stars are cool. Between the classes there were 10 subdivisions numbered 0 to 9. For example, our Sun is a G2 star. Sirius, a hot blue star, is type B3. Why do some stars have strong lines of hydr ...
Stellar Explosions
... very suddenly, burning off the new material. Material keeps being transferred to the white dwarf, and the process repeats, as illustrated here: ...
... very suddenly, burning off the new material. Material keeps being transferred to the white dwarf, and the process repeats, as illustrated here: ...
Document
... approximation for rotating stars. Calculations are especially simple for sun-like stars with a radiative core and convective envelope. ...
... approximation for rotating stars. Calculations are especially simple for sun-like stars with a radiative core and convective envelope. ...
Lecture 12
... There is not a sharp transition between relativistically degenerate and nonrelativistically degenerate gas. Similarly there is no sharp transition between an ideal gas and a completely degenerate one. Partial degeneracy situation requires much more complex solution. White dwarfs Intrinsically faint, ...
... There is not a sharp transition between relativistically degenerate and nonrelativistically degenerate gas. Similarly there is no sharp transition between an ideal gas and a completely degenerate one. Partial degeneracy situation requires much more complex solution. White dwarfs Intrinsically faint, ...
PowerPoint
... a turning point in M at fixed J or in J and fixed baryon mass M0, the sequence is unstable. The side on which M is smaller is more tightly bound - the stable side. The other side is unstable. (The argument for the instability does not imply that one can reach the lower energy state by a dynamical ev ...
... a turning point in M at fixed J or in J and fixed baryon mass M0, the sequence is unstable. The side on which M is smaller is more tightly bound - the stable side. The other side is unstable. (The argument for the instability does not imply that one can reach the lower energy state by a dynamical ev ...
journey to the stars - American Museum of Natural History
... This flow just below the Sun’s surface is similar to the churning of water just before it boils. Go deeper, and we can see the swirling currents of gas that carry the Sun’s energy outward. This energy is generated deep in the center of the Sun by one of the most powerful processes in the Universe. H ...
... This flow just below the Sun’s surface is similar to the churning of water just before it boils. Go deeper, and we can see the swirling currents of gas that carry the Sun’s energy outward. This energy is generated deep in the center of the Sun by one of the most powerful processes in the Universe. H ...
Jovian Planet Systems
... – The solar system certainly lost mass during all phases of its formation (T-tauri, Oort cloud). – Ejection of this material would have drained off ...
... – The solar system certainly lost mass during all phases of its formation (T-tauri, Oort cloud). – Ejection of this material would have drained off ...
How Common is Life in the Milky Way?
... Now work with others in your group to estimate the following quantities based on your new knowledge of astronomy. This is just an estimate, so use powers of 10 to make the math easy. The Milky Way contains about 1011 stars. What fraction of the stars are similar to the Sun? _________________________ ...
... Now work with others in your group to estimate the following quantities based on your new knowledge of astronomy. This is just an estimate, so use powers of 10 to make the math easy. The Milky Way contains about 1011 stars. What fraction of the stars are similar to the Sun? _________________________ ...
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.