5. cosmic distance ladder ii: standard candles
... dwarf, increasing its mass until it begins to collapse under its own weight. As the white dwarf collapses, it heats up, until it reaches 6 × 108 K, the temperature at which carbon fusion occurs. Since white dwarfs are primarily made of carbon, the entire star ignites and explodes, resulting in what ...
... dwarf, increasing its mass until it begins to collapse under its own weight. As the white dwarf collapses, it heats up, until it reaches 6 × 108 K, the temperature at which carbon fusion occurs. Since white dwarfs are primarily made of carbon, the entire star ignites and explodes, resulting in what ...
How do stars appear to move to an observer on the
... Some white dwarfs do not just cool, they have one or more large explosions. Astronomers think this may be caused by a companion star that is having material taken from it by the white dwarf. ...
... Some white dwarfs do not just cool, they have one or more large explosions. Astronomers think this may be caused by a companion star that is having material taken from it by the white dwarf. ...
Ch 3 PPT - Blountstown Middle School
... core collapses quickly under the force of gravity. • The normal space within atoms is eliminated, leaving a dense core of neutrons, or a neutron star. ...
... core collapses quickly under the force of gravity. • The normal space within atoms is eliminated, leaving a dense core of neutrons, or a neutron star. ...
Relation Between the Luminosity of the Star at Different
... Then, different luminosities of Naked Helium stage were analyzed. Through this graph we notice initially a huge decrease in the luminosity and then an increase. This may be explained by the fact that in the Naked Helium stage, the star loses much of its outer surface to the stellar winds. The mass d ...
... Then, different luminosities of Naked Helium stage were analyzed. Through this graph we notice initially a huge decrease in the luminosity and then an increase. This may be explained by the fact that in the Naked Helium stage, the star loses much of its outer surface to the stellar winds. The mass d ...
Habitable Zones around Evolved Stars
... • Stable, slow stages of post-MS evolution for most stars: He core burning, White dwarf cooling • Mass-loss determines Lmax(AGB); uncertainties include the mass loss formula, shell flash effects and which stars become carbon stars • At Lmax planets within about 1AU are engulfed (details depending on ...
... • Stable, slow stages of post-MS evolution for most stars: He core burning, White dwarf cooling • Mass-loss determines Lmax(AGB); uncertainties include the mass loss formula, shell flash effects and which stars become carbon stars • At Lmax planets within about 1AU are engulfed (details depending on ...
Introduction - Cambridge University Press
... The starting point for the formation of a star is a cloud of cold gas, composed primarily of hydrogen and helium, with traces of heavier elements (usually referred to as metals). The cloud collapses due to its own gravity, and as gravitational potential energy is released and converted into heat, th ...
... The starting point for the formation of a star is a cloud of cold gas, composed primarily of hydrogen and helium, with traces of heavier elements (usually referred to as metals). The cloud collapses due to its own gravity, and as gravitational potential energy is released and converted into heat, th ...
Astronomy 15 - Problem Set Number 4 1) Suppose one were to
... exposure takes a considerable amount of time to read out from the chip. The statistical properties of a CCD signal are somewhat similar to those from a photomultiplier, but there are several complicating factors, so a photomultiplier makes a simpler example. Question: Suppose a star delivers about 1 ...
... exposure takes a considerable amount of time to read out from the chip. The statistical properties of a CCD signal are somewhat similar to those from a photomultiplier, but there are several complicating factors, so a photomultiplier makes a simpler example. Question: Suppose a star delivers about 1 ...
Surveying the Stars
... • How massive are stars? • The overall range of stellar masses runs from 0.08 times the mass of the Sun to about 100 times the mass of the Sun. ...
... • How massive are stars? • The overall range of stellar masses runs from 0.08 times the mass of the Sun to about 100 times the mass of the Sun. ...
Section 1
... Although the fundamental physical properties are parameters such as M , R, and L, these translate into observational parameters such as absolute magnitude and colour index (cf. Appendix E), or spectral type. The ultimate goal is to relate these observationally accessible quantities to the physical p ...
... Although the fundamental physical properties are parameters such as M , R, and L, these translate into observational parameters such as absolute magnitude and colour index (cf. Appendix E), or spectral type. The ultimate goal is to relate these observationally accessible quantities to the physical p ...
Ch 28 Class Notes
... The absolute magnitude of a Cepheid is related to the length of time between its periods of maximum brightness. The slower the cycle, the greater the luminosity of the star. By ___________________ a ____________________________________________________________________, astronomers can determine the d ...
... The absolute magnitude of a Cepheid is related to the length of time between its periods of maximum brightness. The slower the cycle, the greater the luminosity of the star. By ___________________ a ____________________________________________________________________, astronomers can determine the d ...
Lecture 8a Star Formation 10/15/2014
... • No heavy elements. Just Hydrogen and Helium • Often outside plane of galaxy Understood as group of old stars formed in early history of the galaxy PHYS 162 Lecture 8a ...
... • No heavy elements. Just Hydrogen and Helium • Often outside plane of galaxy Understood as group of old stars formed in early history of the galaxy PHYS 162 Lecture 8a ...
Neutron Stars PowerPoint
... – Thought to have solid crust of ordinary neutrons – Thought to have fluid interior of degenerate neutrons ...
... – Thought to have solid crust of ordinary neutrons – Thought to have fluid interior of degenerate neutrons ...
Neutron Stars PowerPoint
... – Thought to have solid crust of ordinary neutrons – Thought to have fluid interior of degenerate neutrons ...
... – Thought to have solid crust of ordinary neutrons – Thought to have fluid interior of degenerate neutrons ...
Type II supernova
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, and no more than 40–50 times, the mass of the Sun (M☉) for this type of explosion. It is distinguished from other types of supernovae by the presence of hydrogen in its spectrum. Type II supernovae are mainly observed in the spiral arms of galaxies and in H II regions, but not in elliptical galaxies.Stars generate energy by the nuclear fusion of elements. Unlike the Sun, massive stars possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium, albeit at increasingly higher temperatures and pressures, causing increasingly shorter stellar life spans. The degeneracy pressure of electrons and the energy generated by these fusion reactions are sufficient to counter the force of gravity and prevent the star from collapsing, maintaining stellar equilibrium. The star fuses increasingly higher mass elements, starting with hydrogen and then helium, progressing up through the periodic table until a core of iron and nickel is produced. Fusion of iron or nickel produces no net energy output, so no further fusion can take place, leaving the nickel-iron core inert. Due to the lack of energy output allowing outward pressure, equilibrium is broken.When the mass of the inert core exceeds the Chandrasekhar limit of about 1.4 M☉, electron degeneracy alone is no longer sufficient to counter gravity and maintain stellar equilibrium. A cataclysmic implosion takes place within seconds, in which the outer core reaches an inward velocity of up to 23% of the speed of light and the inner core reaches temperatures of up to 100 billion kelvin. Neutrons and neutrinos are formed via reversed beta-decay, releasing about 1046 joules (100 foes) in a ten-second burst. The collapse is halted by neutron degeneracy, causing the implosion to rebound and bounce outward. The energy of this expanding shock wave is sufficient to accelerate the surrounding stellar material to escape velocity, forming a supernova explosion, while the shock wave and extremely high temperature and pressure briefly allow for theproduction of elements heavier than iron. Depending on initial size of the star, the remnants of the core form a neutron star or a black hole. Because of the underlying mechanism, the resulting nova is also described as a core-collapse supernova.There exist several categories of Type II supernova explosions, which are categorized based on the resulting light curve—a graph of luminosity versus time—following the explosion. Type II-L supernovae show a steady (linear) decline of the light curve following the explosion, whereas Type II-P display a period of slower decline (a plateau) in their light curve followed by a normal decay. Type Ib and Ic supernovae are a type of core-collapse supernova for a massive star that has shed its outer envelope of hydrogen and (for Type Ic) helium. As a result, they appear to be lacking in these elements.