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Constellations
Constellations

... Imagine you are standing at the North Pole and see a star directly overhead. Where do you think the star would be if you were standing at the equator? ...
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Final review - Physics and Astronomy
Final review - Physics and Astronomy

... emissions are detectable. R* =The rate of formation of stars suitable for the development of intelligent life. fp = The fraction of those stars with planetary systems. ne = The number of planets, per solar system, with an environment suitable for life. fl = The fraction of suitable planets on which ...
Geol. 655 Isotope Geochemistry
Geol. 655 Isotope Geochemistry

... Hydrogen, Helium, and Carbon Burning in Main Sequence and Red Giant Stars For quite some time after the Big Bang, the universe was a more or less homogeneous, hot gas. More or less turns out to be critical wording. Inevitably (according to fluid dynamics), inhomogeneities in the gas developed. These ...
ch16 b - Manasquan Public Schools
ch16 b - Manasquan Public Schools

The Star–Gas–Star Cycle
The Star–Gas–Star Cycle

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September Evening Skies

... in binoculars as a 6th-mag. "star" in Aquarius, is plotted as a "+" for mid-September 2005. At chart time 7 objects of first magnitude or brighter are visible. In order of brightness they are: Arcturus, Vega, Capella, Altair, Antares, Fomalhaut, and Deneb. Our usual monthly maps are designed for sta ...
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Stellar Spire in the Eagle Nebula

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The Inverse Square Law and Surface Area

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May 2013 - Otterbein

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Explore the Galaxy - Museum of Science, Boston

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... force of gravity. This is what keeps the sun and most other stars at their present diameters. In those cases the pressure, P, is generated by the motion of the individual particles in the gas, according to P = n kB T where n is the number of particles per unit volume and T is the temperature. (Insid ...
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... inward. Gravity can then pull some of the gas and dust in the nebula together. The contracting cloud is then called a protostar. A protostar is the earliest stage of a star’s life. The inward collapse of material causes the center of the protostar to become very hot and dense. Once the central tempe ...
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"Stars" Power Point notes

... • Light split by a prism into a rainbow is a continuous spectrum. • A continuous spectrum is emitted by hot, dense materials, such as the gas of the Sun’s photosphere. ...
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... Binaries that are able to survive in the dense environment of star cluster (in particular GCs) are so close that even the HST is not able to resolve the single components… So, light coming from each star will combine, and the binary system will appear as a single point-like source… when indicating w ...
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Simplified Nuclear Fusion

... reaction does not occur in one step. In several steps, four hydrogen atoms fuse into helium. This reaction releases energy because the helium atom produced has very slightly less mass than the four hydrogen atoms that started the reaction. In all energy producing nuclear reactions, the total mass of ...
Reach_for_the_stars_final_questions.doc
Reach_for_the_stars_final_questions.doc

... 6. Antares emits a large portion of its energy in what non-visible wavelength? (1 pt) _____________________________________________________________________________________________________ 7. White dwarfs can go supernova when they approach a certain mass. What is the name of this “critical mass”? (1 ...
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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.
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