Chapter 17 Star Stuff
... • A star remains on the main sequence as long as it can fuse hydrogen into helium in its core. • It starts to leave the main sequence once the core is mostly made of helium • Observations of star clusters show that a star becomes larger, redder, and brighter after its time on the main sequence is ov ...
... • A star remains on the main sequence as long as it can fuse hydrogen into helium in its core. • It starts to leave the main sequence once the core is mostly made of helium • Observations of star clusters show that a star becomes larger, redder, and brighter after its time on the main sequence is ov ...
Refusing to Go Quietly: GRBs and Their Progenitors
... • If they are very far, their energies may be stupendous....something like the rest mass of the sun being turned into gamma-rays! ...
... • If they are very far, their energies may be stupendous....something like the rest mass of the sun being turned into gamma-rays! ...
Presentation
... •If oblate proto neutron stars are formed due to centrifugal forces, more neutrinos are emitted in the direction of rotation axis. • Assuming an oblate proto neutron star is formed, we carried out hydrodynamic simulation, and found that n-heating is enhanced near the rotation axis, and global convec ...
... •If oblate proto neutron stars are formed due to centrifugal forces, more neutrinos are emitted in the direction of rotation axis. • Assuming an oblate proto neutron star is formed, we carried out hydrodynamic simulation, and found that n-heating is enhanced near the rotation axis, and global convec ...
The Life Cycle of Stars
... When a massive star runs out of hydrogen for fusion, it begins to fuse helium into carbon (like our Sun). The core of a massive star becomes so hot that when helium is no longer available for fusion, carbon undergoes fusion. This produces heavier elements, beginning with oxygen and up to iron. Once ...
... When a massive star runs out of hydrogen for fusion, it begins to fuse helium into carbon (like our Sun). The core of a massive star becomes so hot that when helium is no longer available for fusion, carbon undergoes fusion. This produces heavier elements, beginning with oxygen and up to iron. Once ...
Chapter12 (with interactive links)
... The star ionizes the gas in the expanding outer layers, causing the planetary nebula that we can observe. Planetary nebulae do not last forever – eventually the gas disperses. ...
... The star ionizes the gas in the expanding outer layers, causing the planetary nebula that we can observe. Planetary nebulae do not last forever – eventually the gas disperses. ...
ASTR 1101-001 Spring 2008 - Louisiana State University
... • Easily (and now frequently) detected in other galaxies. (Statistically, every galaxy should display 1-3 supernovae every 100 yrs.) • The light display from each SN generally can be categorized as one of several standard “types”: – Type Ia – Type Ib, Ic – Type II ...
... • Easily (and now frequently) detected in other galaxies. (Statistically, every galaxy should display 1-3 supernovae every 100 yrs.) • The light display from each SN generally can be categorized as one of several standard “types”: – Type Ia – Type Ib, Ic – Type II ...
MAIN SEQUENCE STARS, Red Giants and White Dwarfs
... • 16O + 4He 20Ne + • 20Ne + 4He 24Mg + • We’ll come back to this type of onion-layer model star when we talk about supernova explosions and neutron stars. • The elements cooked here are needed for life ...
... • 16O + 4He 20Ne + • 20Ne + 4He 24Mg + • We’ll come back to this type of onion-layer model star when we talk about supernova explosions and neutron stars. • The elements cooked here are needed for life ...
Post Main Sequence Evolution Since a star`s luminosity on the main
... The Hertzsprung Gap and the Subgiant Phase • When the Schönberg-Chandrasekhar limit is reached, the star must change its structure. First, core contraction begins to occur on the Kelvin-Helmholtz timescale, and the rapid increase in core density causes an increase in the temperatures and densities ...
... The Hertzsprung Gap and the Subgiant Phase • When the Schönberg-Chandrasekhar limit is reached, the star must change its structure. First, core contraction begins to occur on the Kelvin-Helmholtz timescale, and the rapid increase in core density causes an increase in the temperatures and densities ...
What is a white dwarf?
... What is a white dwarf? • A white dwarf is the core left over from a low-mass star, supported against the crush of gravity by electron degeneracy pressure. • What can happen to a white dwarf in a close binary system? • It can acquire hydrogen from its companion through an accretion disk. As hydrogen ...
... What is a white dwarf? • A white dwarf is the core left over from a low-mass star, supported against the crush of gravity by electron degeneracy pressure. • What can happen to a white dwarf in a close binary system? • It can acquire hydrogen from its companion through an accretion disk. As hydrogen ...
Chapter 15 Surveying the Stars
... • What is a Hertzsprung-Russell diagram? • What is the significance of the main sequence? • What are giants, supergiants, and white dwarfs? • Why do the properties of some stars vary? ...
... • What is a Hertzsprung-Russell diagram? • What is the significance of the main sequence? • What are giants, supergiants, and white dwarfs? • Why do the properties of some stars vary? ...
Astronomy 104: Stellar Astronomy
... Where the Elements came from? • Big Bang made 75% H, 25% He – stars make everything else! ...
... Where the Elements came from? • Big Bang made 75% H, 25% He – stars make everything else! ...
Powerpoint
... Reactions below 24Mg, e.g., 20Ne(ag)24Mg and 12C(ag)16O are, in general, not in equilibrium with their inverses (exception, 16O(ag)20Ne which has been in equilibrium since neon burning). Within the groups heavier than A = 24, except at the boundaries of the clusters, the abundance of any species ...
... Reactions below 24Mg, e.g., 20Ne(ag)24Mg and 12C(ag)16O are, in general, not in equilibrium with their inverses (exception, 16O(ag)20Ne which has been in equilibrium since neon burning). Within the groups heavier than A = 24, except at the boundaries of the clusters, the abundance of any species ...
Solutions to Homework #4, AST 203, Spring 2012
... Hint: the Earth is still very far from this planetary system. Solution We are observing this transit from very far away, so the distance between the planet and the host star will not affect the answer. The difference is just the cross sectional area of the planet. Jupiter’s radius is 11 times the Ea ...
... Hint: the Earth is still very far from this planetary system. Solution We are observing this transit from very far away, so the distance between the planet and the host star will not affect the answer. The difference is just the cross sectional area of the planet. Jupiter’s radius is 11 times the Ea ...
Luminosity
... • What is a Hertzsprung-Russell diagram? • What is the significance of the main sequence? • What are giants, supergiants, and white dwarfs? • Why do the properties of some stars vary? ...
... • What is a Hertzsprung-Russell diagram? • What is the significance of the main sequence? • What are giants, supergiants, and white dwarfs? • Why do the properties of some stars vary? ...
Lecture 13 Main Sequence and Low Mass Evolution
... • The higher the mass, the shorter its life. • Examples: Sun: ~ 10 Billion Years 30 Msun O‐star: ~ 2 Million years 0.1 Msun M‐star: ~ 3 Trillion years ...
... • The higher the mass, the shorter its life. • Examples: Sun: ~ 10 Billion Years 30 Msun O‐star: ~ 2 Million years 0.1 Msun M‐star: ~ 3 Trillion years ...
AST1001.ch13
... — Measure velocity and distance of orbiting gas • It’s a black hole if it’s not a star and its mass exceeds the neutron star limit (~3 MSun). ...
... — Measure velocity and distance of orbiting gas • It’s a black hole if it’s not a star and its mass exceeds the neutron star limit (~3 MSun). ...
Chapter 17 Star Stuff Agenda How does a star`s mass affect nuclear
... • The mass of a main sequence star determines its core pressure and temperature • Stars of higher mass have higher core temperature and more rapid fusion, making those stars both more luminous and shorter-lived • Stars of lower mass have cooler cores and slower fusion rates, giving them smaller lumi ...
... • The mass of a main sequence star determines its core pressure and temperature • Stars of higher mass have higher core temperature and more rapid fusion, making those stars both more luminous and shorter-lived • Stars of lower mass have cooler cores and slower fusion rates, giving them smaller lumi ...
GoldCreation
... One of my favorite astronomy-themed t-shirts says “You are star dust”. It makes the point that we are all made from long dead stars. Of course, everything around us is also made of star stuff. This even includes rare elements such as gold. This paper discusses the processes of gold formation. Most m ...
... One of my favorite astronomy-themed t-shirts says “You are star dust”. It makes the point that we are all made from long dead stars. Of course, everything around us is also made of star stuff. This even includes rare elements such as gold. This paper discusses the processes of gold formation. Most m ...
SUMMARY White dwarfs, neutron stars, and black holes are the
... perfectly flat. Try rolling a marble across the fabric from one side to the other—does it travel more or less in a straight line? If we add an object with mass, space will stretch around the object. Create a circle with a piece of string, and compare the radius measured across it with what you get d ...
... perfectly flat. Try rolling a marble across the fabric from one side to the other—does it travel more or less in a straight line? If we add an object with mass, space will stretch around the object. Create a circle with a piece of string, and compare the radius measured across it with what you get d ...
Stages 7 to 9 - Sun
... While on the main sequence, the star is burning hydrogen. It’s luminosity is determined by the stars mass. The most intense fusion is occurring at the center regions of the core (highest pressure and temperature). ...
... While on the main sequence, the star is burning hydrogen. It’s luminosity is determined by the stars mass. The most intense fusion is occurring at the center regions of the core (highest pressure and temperature). ...
chapter17StarStuff
... What happens in a low-mass star when core temperature rises enough for helium fusion to begin? A. Helium fusion slowly starts up B. Hydrogen fusion stops C. Helium fusion rises very sharply Hint: Degeneracy pressure is the main form of pressure in the inert helium core ...
... What happens in a low-mass star when core temperature rises enough for helium fusion to begin? A. Helium fusion slowly starts up B. Hydrogen fusion stops C. Helium fusion rises very sharply Hint: Degeneracy pressure is the main form of pressure in the inert helium core ...
Lecture20
... When it became a red giant, material was ejected Helium fusion last about 1 million years forming a core of carbon and oxygen When the helium was exhausted, carbon and oxygen burning began and the star became a blue supergiant When the carbon was exhausted, burning to heavier elements only lasted fo ...
... When it became a red giant, material was ejected Helium fusion last about 1 million years forming a core of carbon and oxygen When the helium was exhausted, carbon and oxygen burning began and the star became a blue supergiant When the carbon was exhausted, burning to heavier elements only lasted fo ...
D2 Stellar characteristics and stellar evolution
... times larger. If placed at the center of our Solar System, it would extend past the orbit of Jupiter (has an immense but highly variable, outer atmosphere ). As a massive red supergiant, it is nearing the end of its life and will soon become a supernova ...
... times larger. If placed at the center of our Solar System, it would extend past the orbit of Jupiter (has an immense but highly variable, outer atmosphere ). As a massive red supergiant, it is nearing the end of its life and will soon become a supernova ...
Life in the galactic danger zone
... sterilise a larger number of worlds because the density of stars there is greater. However, he disagrees that high metallicity environments always allow hot jupiters to run rampant. “In contrast to Lineweaver, we used the results of radial velocity planet searches in combination with a model of plan ...
... sterilise a larger number of worlds because the density of stars there is greater. However, he disagrees that high metallicity environments always allow hot jupiters to run rampant. “In contrast to Lineweaver, we used the results of radial velocity planet searches in combination with a model of plan ...
Lect15-3-23-11-stars..
... 2. Second, as the gas cloud continues to collapse, radiating into space essentially all of the heat generated from gravitational potential energy release, its surface temperature warms only slightly. However, as the collapse proceeds, the surface area of the cloud is diminished,, so that its luminos ...
... 2. Second, as the gas cloud continues to collapse, radiating into space essentially all of the heat generated from gravitational potential energy release, its surface temperature warms only slightly. However, as the collapse proceeds, the surface area of the cloud is diminished,, so that its luminos ...
Supernova
A supernova is a stellar explosion that briefly outshines an entire galaxy, radiating as much energy as the Sun or any ordinary star is expected to emit over its entire life span, before fading from view over several weeks or months. The extremely luminous burst of radiation expels much or all of a star's material at a velocity of up to 7007300000000000000♠30,000 km/s (10% of the speed of light), driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant. Supernovae are potentially strong galactic sources of gravitational waves. A great proportion of primary cosmic rays comes from supernovae.Supernovae are more energetic than novae. Nova means ""new"" in Latin, referring to what appears to be a very bright new star shining in the celestial sphere; the prefix ""super-"" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky in 1931. It is pronounced /ˌsuːpərnoʊvə/ with the plural supernovae /ˌsuːpərnoʊviː/ or supernovas (abbreviated SN, plural SNe after ""supernovae"").Supernovae can be triggered in one of two ways: by the sudden re-ignition of nuclear fusion in a degenerate star; or by the gravitational collapse of the core of a massive star. In the first case, a degenerate white dwarf may accumulate sufficient material from a companion, either through accretion or via a merger, to raise its core temperature, ignite carbon fusion, and trigger runaway nuclear fusion, completely disrupting the star. In the second case, the core of a massive star may undergo sudden gravitational collapse, releasing gravitational potential energy that can create a supernova explosion.The most recent directly observed supernova in the Milky Way was Kepler's Star of 1604 (SN 1604); remnants of two more recent supernovae have been found retrospectively. Observations in other galaxies indicate that supernovae should occur on average about three times every century in the Milky Way, and that any galactic supernova would almost certainly be observable in modern astronomical equipment. Supernovae play a significant role in enriching the interstellar medium with higher mass elements. Furthermore, the expanding shock waves from supernova explosions can trigger the formation of new stars.