Heavy Metal from Ancient Superstars
... of Stars The chemical compositions of stars reflect the star formation histories of stellar populations The complexity of the Milky Way’s history is reflected in the compositions of its stars ...
... of Stars The chemical compositions of stars reflect the star formation histories of stellar populations The complexity of the Milky Way’s history is reflected in the compositions of its stars ...
Theory of the Infinite Universe
... Stars provide vast amounts of energy for millions of years through the process of nuclear fusion. Nuclear fusion occurs when two elements are fused together to form a heavier element. This process r ...
... Stars provide vast amounts of energy for millions of years through the process of nuclear fusion. Nuclear fusion occurs when two elements are fused together to form a heavier element. This process r ...
6.1 Sun - TeacherWeb
... The mass of the sun makes up 99.8% of all of the mass in the solar system. ...
... The mass of the sun makes up 99.8% of all of the mass in the solar system. ...
Laboratory Title
... When the temperature at the core of a protostar reaches 27,000,000°F, nuclear fusion starts. The nuclear fusion is taking the hydrogen atoms and smashing them together to form a helium atom. This releases a tremendous amount of energy. The majority of stars in the universe are main sequence stars (i ...
... When the temperature at the core of a protostar reaches 27,000,000°F, nuclear fusion starts. The nuclear fusion is taking the hydrogen atoms and smashing them together to form a helium atom. This releases a tremendous amount of energy. The majority of stars in the universe are main sequence stars (i ...
Stellar Spire in the Eagle Nebula
... gas that reside in chaotic neighborhoods, where energy from newborn stars sculpts fantasy-like landscapes in the gas. The tower is a giant incubator for these newborn stars. A torrent of ultraviolet light from a band of massive, hot, young stars [off the top of the image] is eroding the pillar. The ...
... gas that reside in chaotic neighborhoods, where energy from newborn stars sculpts fantasy-like landscapes in the gas. The tower is a giant incubator for these newborn stars. A torrent of ultraviolet light from a band of massive, hot, young stars [off the top of the image] is eroding the pillar. The ...
HR DIAGRAM ACTIVITY
... You can check your HR diagram at: http://deskarati.com/wp-content/uploads/2012/03/HertzsprungRussell-Diagram.jpg 1. Draw a circle around all the red giants on your graph and label this enclosed area Red Giants. 2. Draw a circle around all the white dwarfs and label this enclosed area White Dwarfs. 3 ...
... You can check your HR diagram at: http://deskarati.com/wp-content/uploads/2012/03/HertzsprungRussell-Diagram.jpg 1. Draw a circle around all the red giants on your graph and label this enclosed area Red Giants. 2. Draw a circle around all the white dwarfs and label this enclosed area White Dwarfs. 3 ...
Luminosity and brightness
... (b) the distance of the star from the observer on the Earth If we have two stars of the same luminosity with one star double the distance of the other from the Earth the closer star will look four times brighter. It obeys the inverse square law. The photograph shows the Pleiades star cluster. The br ...
... (b) the distance of the star from the observer on the Earth If we have two stars of the same luminosity with one star double the distance of the other from the Earth the closer star will look four times brighter. It obeys the inverse square law. The photograph shows the Pleiades star cluster. The br ...
Lecture Ten - The Sun Amongst the Stars Part II
... The reason behind this relationship between mass and luminosity in stars first began to become clear in the early 20 th century, when physicists like Einstein revealed that atoms possess a type of potential energy based only on how massive they are. This mass energy can be changed by altering the at ...
... The reason behind this relationship between mass and luminosity in stars first began to become clear in the early 20 th century, when physicists like Einstein revealed that atoms possess a type of potential energy based only on how massive they are. This mass energy can be changed by altering the at ...
The Luna experiment - EPJ Web of Conferences
... ratio between carbon and oxygen, the two key elements to the development of life, and it shapes the nucleosynthesis in massive stars affecting the outcomes of both thermonuclear and core-collapse supernovae. Equally important are 13 C(α,n)16 O and 22 Ne(α,n)25 Mg, the sources of the neutrons which sy ...
... ratio between carbon and oxygen, the two key elements to the development of life, and it shapes the nucleosynthesis in massive stars affecting the outcomes of both thermonuclear and core-collapse supernovae. Equally important are 13 C(α,n)16 O and 22 Ne(α,n)25 Mg, the sources of the neutrons which sy ...
1. How old is our sun now? How does its present luminosity
... dropping off, as would be expected based on the visible starlight. (b) In clusters of galaxies, the galaxies move with high velocities, which indicates a stronger gravitational field that predicted by the mass of the galaxies and gas seen in the cluster. There are other possible answers: cosmologica ...
... dropping off, as would be expected based on the visible starlight. (b) In clusters of galaxies, the galaxies move with high velocities, which indicates a stronger gravitational field that predicted by the mass of the galaxies and gas seen in the cluster. There are other possible answers: cosmologica ...
Stars and Light
... cooler brown dwarf stars. These stars have such low masses, < 0.08 M⊙, that no fusion occurs inside. Spectral class M include the most massive brown dwarfs. • Need extra spectral types: L, T, Y • L is hottest, Y is coolest (down to ~300K) • Note Y brown dwarfs were discovered only this year and are ...
... cooler brown dwarf stars. These stars have such low masses, < 0.08 M⊙, that no fusion occurs inside. Spectral class M include the most massive brown dwarfs. • Need extra spectral types: L, T, Y • L is hottest, Y is coolest (down to ~300K) • Note Y brown dwarfs were discovered only this year and are ...
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.