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... are about to form new stars. They also create the heavier elements (such as gold, silver, lead, and uranium) and distribute these as well. Their remnants generate the cosmic rays which lead to mutation and evolution in living cells. These supernovae, then, are key to the evolution of the Universe an ...
... are about to form new stars. They also create the heavier elements (such as gold, silver, lead, and uranium) and distribute these as well. Their remnants generate the cosmic rays which lead to mutation and evolution in living cells. These supernovae, then, are key to the evolution of the Universe an ...
Solar Furnaces
... Sun’s core has about 15% of Sun’s mass Sun is mostly hydrogen: 70% H, 28% He, 2% heavier stuff • Sun’s main-sequence life about 10 billion years! • Note that photons take about 105 years just to leak out. • All main sequence stars are fusing H to He, but in stars more massive than 1.5 Msun, the pp c ...
... Sun’s core has about 15% of Sun’s mass Sun is mostly hydrogen: 70% H, 28% He, 2% heavier stuff • Sun’s main-sequence life about 10 billion years! • Note that photons take about 105 years just to leak out. • All main sequence stars are fusing H to He, but in stars more massive than 1.5 Msun, the pp c ...
Slide 1
... After the Sun's core hydrogen is depleted by nuclear fusion the core will consist primarily of 1) carbon. 2) deuterium. 3) helium. 4) oxygen. ...
... After the Sun's core hydrogen is depleted by nuclear fusion the core will consist primarily of 1) carbon. 2) deuterium. 3) helium. 4) oxygen. ...
The death of a star
... This rate of expansion continues and the star expands to produce a Red Giant the size of the Earth's orbit. This expansion is so rapid that the outer layers will cool, their temperature falling from the 6000o of its main lifetime to some 3000o in the Red Giant phase. The core is still hot and contin ...
... This rate of expansion continues and the star expands to produce a Red Giant the size of the Earth's orbit. This expansion is so rapid that the outer layers will cool, their temperature falling from the 6000o of its main lifetime to some 3000o in the Red Giant phase. The core is still hot and contin ...
Life Cycles of Stars
... white dwarf star that suddenly increases in brightness by several magnitudes. It fades very slowly. ...
... white dwarf star that suddenly increases in brightness by several magnitudes. It fades very slowly. ...
We Are All Star Dust - High School of Language and Innovation
... • Temperature inside of the core of the Sun = 27,000,000°F • Most of the universe is made from hydrogen and helium ...
... • Temperature inside of the core of the Sun = 27,000,000°F • Most of the universe is made from hydrogen and helium ...
Stages in the Formation of Stars
... 3. Name the process that causes a star to begin producing vast amounts of energy. _____________________________________________ 4. What two processes balance each other to make a star stable? ...
... 3. Name the process that causes a star to begin producing vast amounts of energy. _____________________________________________ 4. What two processes balance each other to make a star stable? ...
The Hidden Lives of Galaxies NSTA 2001
... exhausted their core nuclear fuel and which have too little gravity to contract further. They have no new source of energy and are cooling into ...
... exhausted their core nuclear fuel and which have too little gravity to contract further. They have no new source of energy and are cooling into ...
A Star’s Life
... large star by explosion So massive light cannot escape. The mass of 3 suns and about 6 miles across ...
... large star by explosion So massive light cannot escape. The mass of 3 suns and about 6 miles across ...
Stars and Their Characteristics
... • nebula may condense when an outside force acts upon it • particles move closer together under gravity • increase density = increase temperature • if nebula glows, called protostar • center will become hotter until fusion takes place and a star is born ...
... • nebula may condense when an outside force acts upon it • particles move closer together under gravity • increase density = increase temperature • if nebula glows, called protostar • center will become hotter until fusion takes place and a star is born ...
The Hidden Lives of Galaxies NSTA 2001
... Recall Stars have Different colors which indicate different temperatures ...
... Recall Stars have Different colors which indicate different temperatures ...
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.