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... 6. What two star characteristics does the Hertzsprung-Russell diagram compare? 7. What is a star’s spectrum? ...
... 6. What two star characteristics does the Hertzsprung-Russell diagram compare? 7. What is a star’s spectrum? ...
Stars - TeacherWeb
... • any object 15 to 75 times the mass of Jupiter • the object would not have been able to sustain fusion like a regular star - called "failed stars" • all are parts of a binary system. (two stars orbit around one another) • possible that brown dwarfs represent a lot of the mass in the universe ...
... • any object 15 to 75 times the mass of Jupiter • the object would not have been able to sustain fusion like a regular star - called "failed stars" • all are parts of a binary system. (two stars orbit around one another) • possible that brown dwarfs represent a lot of the mass in the universe ...
doc
... flash” (see p. 533): energy gets soaked up by the huge “buffer” of the envelope, so virtually unobservable from the outside—but very well established theoretically—note how almost all of this is stellar evolution theory). Eventually (after only a few hours or less), the huge energy input does cause ...
... flash” (see p. 533): energy gets soaked up by the huge “buffer” of the envelope, so virtually unobservable from the outside—but very well established theoretically—note how almost all of this is stellar evolution theory). Eventually (after only a few hours or less), the huge energy input does cause ...
Neutron Stars
... Upper mass limit of Neutron Stars • In Neutron stars the gravity is balanced by two forces. – Degenerate neutron pressure – Strong nuclear force. ...
... Upper mass limit of Neutron Stars • In Neutron stars the gravity is balanced by two forces. – Degenerate neutron pressure – Strong nuclear force. ...
The Science behind the Stars ctY Astrophysics by Spencer McClung
... of stars with three helium atoms combining to form a carbon atom. For the most massive stars, this continues until finally iron is formed. Then the weight is so great that the star collapses in on itself and explodes in a supernova, which is how almost every atom heavier than iron is created. That m ...
... of stars with three helium atoms combining to form a carbon atom. For the most massive stars, this continues until finally iron is formed. Then the weight is so great that the star collapses in on itself and explodes in a supernova, which is how almost every atom heavier than iron is created. That m ...
RED GIANTS
... When core hydrogen fusion ceases, a main-sequence star becomes a giant • The star can no longer support its weight • The enormous weight from the outer layers compresses hydrogen in the layers just outside the core enough to initiate shell hydrogen fusion. • This extra internal heat causes the oute ...
... When core hydrogen fusion ceases, a main-sequence star becomes a giant • The star can no longer support its weight • The enormous weight from the outer layers compresses hydrogen in the layers just outside the core enough to initiate shell hydrogen fusion. • This extra internal heat causes the oute ...
Lifecycle of Stars
... 1) Once your teacher has approved each word timeline and you have recorded them on the back of this page, you will create a personal poster that visually displays the four life cycles. You will work in table teams to complete this process, but you will each create your own mini-poster. 2) Use your n ...
... 1) Once your teacher has approved each word timeline and you have recorded them on the back of this page, you will create a personal poster that visually displays the four life cycles. You will work in table teams to complete this process, but you will each create your own mini-poster. 2) Use your n ...
Stars
... • If the white dwarf is close to the 1.4 solar mass upper limit that electron degeneracy can support… • The added mass could push it past the limit before it gets hot enough to flash off • Then, star collapses under the weight and because it is electron degenerate, energy created will not expand the ...
... • If the white dwarf is close to the 1.4 solar mass upper limit that electron degeneracy can support… • The added mass could push it past the limit before it gets hot enough to flash off • Then, star collapses under the weight and because it is electron degenerate, energy created will not expand the ...
Document
... b. produced by a supernova explosion. c. produced by a nova explosion. d. a nebula within which planets are forming. e. a cloud of hot gas surrounding a planet. 22. Massive stars cannot generate energy through iron fusion because a. iron fusion requires very high density. b. stars contain very littl ...
... b. produced by a supernova explosion. c. produced by a nova explosion. d. a nebula within which planets are forming. e. a cloud of hot gas surrounding a planet. 22. Massive stars cannot generate energy through iron fusion because a. iron fusion requires very high density. b. stars contain very littl ...
Astronomy 112: Physics of Stars Problem set 2: Due April 29 1. Time
... 8. Polytropes: Helium burning: We shall see later that after they finish central and shell hydrogen burning, many stars, including the sun, go on to ignite helium burning in their centers at a temperature ∼ 1.5×108 K. (aside: This temperature does not vary very much due to the extreme temperature se ...
... 8. Polytropes: Helium burning: We shall see later that after they finish central and shell hydrogen burning, many stars, including the sun, go on to ignite helium burning in their centers at a temperature ∼ 1.5×108 K. (aside: This temperature does not vary very much due to the extreme temperature se ...
CBradleyLoutl
... whole cloud into a number of condensed groups, if a group has over a certain mass, gravity will be strong enough to condense it into a star. First, a high mass cloud will contract, then begin breaking apart and each individual mass will break apart and contract at different rates (depending on the m ...
... whole cloud into a number of condensed groups, if a group has over a certain mass, gravity will be strong enough to condense it into a star. First, a high mass cloud will contract, then begin breaking apart and each individual mass will break apart and contract at different rates (depending on the m ...
The Sun and the Stars
... • What is the single most distinguishing feature of a star? • Luminosity is a term that astronomers use when describing the total amount of energy it radiated by the star ( the twinkle) • It can be measured more precisely as a star’s total energy output per second, measured in Joules per second (J/s ...
... • What is the single most distinguishing feature of a star? • Luminosity is a term that astronomers use when describing the total amount of energy it radiated by the star ( the twinkle) • It can be measured more precisely as a star’s total energy output per second, measured in Joules per second (J/s ...
The H-R Diagram
... main sequence. Most white dwarfs have approximately the mass of the sun, but a radius about 0.01 to 0.001 of the radius of the sun (roughly about the size of a the earth). Their average density is about 106 to 108 solar density. They have exhausted all of their nuclear fuel, are no longer generating ...
... main sequence. Most white dwarfs have approximately the mass of the sun, but a radius about 0.01 to 0.001 of the radius of the sun (roughly about the size of a the earth). Their average density is about 106 to 108 solar density. They have exhausted all of their nuclear fuel, are no longer generating ...
here
... outward force – radiation pressure. For too massive stars, radiation pressure would exceed gravity, know as the “Eddington limit”, which prevents such stars from forming. However, these limits are disputed (see e.g. https://en.wikipedia.org/wiki/R136a1), and the lifetimes of such stars become so sho ...
... outward force – radiation pressure. For too massive stars, radiation pressure would exceed gravity, know as the “Eddington limit”, which prevents such stars from forming. However, these limits are disputed (see e.g. https://en.wikipedia.org/wiki/R136a1), and the lifetimes of such stars become so sho ...
Slide 1
... • Most of you will explain how a star’s fate depends on its mass • Most of you will explain how a supernova leaves a neutron star or a black hole • Some of you will explain how elements made in stars become part of new stars and planets ...
... • Most of you will explain how a star’s fate depends on its mass • Most of you will explain how a supernova leaves a neutron star or a black hole • Some of you will explain how elements made in stars become part of new stars and planets ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.