Stars
... • When a star uses much of it helium, it contracts even more and its outer layers escape into space. • This leaves behind the hot, dense core and the star becomes a white dwarf. • A white dwarf is about the size of Earth. • Eventually, the white dwarf will cool and stop giving off light. ...
... • When a star uses much of it helium, it contracts even more and its outer layers escape into space. • This leaves behind the hot, dense core and the star becomes a white dwarf. • A white dwarf is about the size of Earth. • Eventually, the white dwarf will cool and stop giving off light. ...
Astronomy Test Review
... seen from Earth where as absolute magnitude is the brightness of a star from a standard distance. (10 parsecs) ...
... seen from Earth where as absolute magnitude is the brightness of a star from a standard distance. (10 parsecs) ...
Eclipsing Binaries
... If the binary stars are eclipsing, then it is guaranteed that we are in the orbital plane. This means that the maximum radial velocity on the velocity plot gives us the orbital velocity. Now we have “a” and we have “P”. We can get rid of one of the “M”s because we know how they are related. ...
... If the binary stars are eclipsing, then it is guaranteed that we are in the orbital plane. This means that the maximum radial velocity on the velocity plot gives us the orbital velocity. Now we have “a” and we have “P”. We can get rid of one of the “M”s because we know how they are related. ...
Section 14.7: The Sun
... So bright that you can’t see other stars until the sun has set Provides energy needed by all plants and animals Its gravitational pull keeps us in our steady orbit 1.4 million km across (the earth is only 13000 km across) To compare sizes, if the Sun is a basketball, the Earth would be the ...
... So bright that you can’t see other stars until the sun has set Provides energy needed by all plants and animals Its gravitational pull keeps us in our steady orbit 1.4 million km across (the earth is only 13000 km across) To compare sizes, if the Sun is a basketball, the Earth would be the ...
Most Basic Observations Of the Sun
... center of the Sun using the Gas pressure term alone and using the value for pressure we derived in the previous example. ...
... center of the Sun using the Gas pressure term alone and using the value for pressure we derived in the previous example. ...
Startalk
... The Hertzsprung-Russell Diagram. The Sun, 12 brightest stars of the Northern Hemisphere and white dwarf companion stars to Sirius and Procyon are shown. ...
... The Hertzsprung-Russell Diagram. The Sun, 12 brightest stars of the Northern Hemisphere and white dwarf companion stars to Sirius and Procyon are shown. ...
The Sun - University of Redlands
... particles stripped from the Sun’s surface. • When charged particles and magnetic fields interact: ...
... particles stripped from the Sun’s surface. • When charged particles and magnetic fields interact: ...
Chapter 12
... The Death of a Star -When a star starts to run out of hydrogen fuel I it becomes a red giant or a super giant. - Red giants grow bigger and form a cloud of gas called a planetary nebula. As it cools, it becomes a white dwarf which will eventually run out of fuel and die becoming a black dwarf. -Red ...
... The Death of a Star -When a star starts to run out of hydrogen fuel I it becomes a red giant or a super giant. - Red giants grow bigger and form a cloud of gas called a planetary nebula. As it cools, it becomes a white dwarf which will eventually run out of fuel and die becoming a black dwarf. -Red ...
and Concept Self-test (1,2,3,5,6,7,8,9)
... Neutron stars can also have magnetic fields a million times stronger than the strongest magnetic fields produced on Earth. Neutron stars are one of the possible ends for a star. They result from massive stars which have mass greater than 4 to 8 times that of our Sun. After these stars have finished ...
... Neutron stars can also have magnetic fields a million times stronger than the strongest magnetic fields produced on Earth. Neutron stars are one of the possible ends for a star. They result from massive stars which have mass greater than 4 to 8 times that of our Sun. After these stars have finished ...
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.