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... to the protostar’s surface. Additional radiated energy comes from nuclear fusion and the quasistatic contraction of the interior. However, these contributions are minor compared to Lacc for low and intermediate masses. It is therefore conventional to define a protostar as a mass-gaining star whose l ...
... to the protostar’s surface. Additional radiated energy comes from nuclear fusion and the quasistatic contraction of the interior. However, these contributions are minor compared to Lacc for low and intermediate masses. It is therefore conventional to define a protostar as a mass-gaining star whose l ...
Atoms and the Periodic Table Atoms and Elements
... Below is a table showing the number of protons, electrons, and neutrons for the first ten atoms. The atomic number is the same as the number of protons in the nucleus. The number of electrons in a neutral atom is equal to the number of protons in the nucleus. The number of neutrons in the nucleus ca ...
... Below is a table showing the number of protons, electrons, and neutrons for the first ten atoms. The atomic number is the same as the number of protons in the nucleus. The number of electrons in a neutral atom is equal to the number of protons in the nucleus. The number of neutrons in the nucleus ca ...
Powerpoint
... Ellipticals also contain very little, if any, cool gas and dust, and show no evidence of ongoing star ...
... Ellipticals also contain very little, if any, cool gas and dust, and show no evidence of ongoing star ...
Black Holes
... Neutron stars are compact objects that are created in the cores of massive stars during supernova explosions. The core of the star collapses, and crushes together every proton with a corresponding electron turning each electron-proton pair into a neutron. The neutrons, however, can often stop the co ...
... Neutron stars are compact objects that are created in the cores of massive stars during supernova explosions. The core of the star collapses, and crushes together every proton with a corresponding electron turning each electron-proton pair into a neutron. The neutrons, however, can often stop the co ...
46. HKU Astronomers Discover Complex Organic Matter in the
... Prof. Sun Kwok and Dr. Yong Zhang of The University of Hong Kong show that an organic substance commonly found throughout the Universe contains a mixture of aromatic (ring-like) and aliphatic (chain-like) components. The compounds are so complex that their chemical structures resemble those of coal ...
... Prof. Sun Kwok and Dr. Yong Zhang of The University of Hong Kong show that an organic substance commonly found throughout the Universe contains a mixture of aromatic (ring-like) and aliphatic (chain-like) components. The compounds are so complex that their chemical structures resemble those of coal ...
X-ray output should be time variable
... Bright stars in the spectral range earlier than about B3 are soft X-ray sources, with LX ~ 10-7 LBol THEORY •O star X-ray emission comes from shock-heated gas present in their stellar winds; for B stars, the situation is more uncertain, and their Xrays may be related to magnetic fields, at least in ...
... Bright stars in the spectral range earlier than about B3 are soft X-ray sources, with LX ~ 10-7 LBol THEORY •O star X-ray emission comes from shock-heated gas present in their stellar winds; for B stars, the situation is more uncertain, and their Xrays may be related to magnetic fields, at least in ...
Colors of Stars: Teacher Lesson Plan
... projector. Each group may refer to these images, as well as their drawings, to describe their flame. In stars, just as in Earth-bound fires, blue is hotter than yellow, and yellow is hotter than red. The Sun is much hotter than a candle flame. Unlike a candle, the Sun uses nuclear fusion as its ener ...
... projector. Each group may refer to these images, as well as their drawings, to describe their flame. In stars, just as in Earth-bound fires, blue is hotter than yellow, and yellow is hotter than red. The Sun is much hotter than a candle flame. Unlike a candle, the Sun uses nuclear fusion as its ener ...
The Sun - Tvining.us
... Two mass-1 isotopes of hydrogen undergo a simultaneous fusion and beta decay to produce a positron, a neutrino, and a mass-2 isotope of hydrogen (deuterium). The deuterium reacts with another mass-1 isotope of hydrogen to produce Helium-3 and a gamma-ray. Two helium-3 isotopes produced in separate i ...
... Two mass-1 isotopes of hydrogen undergo a simultaneous fusion and beta decay to produce a positron, a neutrino, and a mass-2 isotope of hydrogen (deuterium). The deuterium reacts with another mass-1 isotope of hydrogen to produce Helium-3 and a gamma-ray. Two helium-3 isotopes produced in separate i ...
CCD PHOTOMETRY OF OPEN STAR CLUSTER M67
... old open star cluster. The distance and age of open star clusters can be determined by comparison of the process of main sequence with a theoretical model. Theoretical isochrones used in this work were published by Bertelli et al. (1994), and include models for different chemical composition and age ...
... old open star cluster. The distance and age of open star clusters can be determined by comparison of the process of main sequence with a theoretical model. Theoretical isochrones used in this work were published by Bertelli et al. (1994), and include models for different chemical composition and age ...
Our galaxy, the Milky Way, has about 3 billion solar masses of HI
... diameter) disk of stars and gas and dust around a central bulge and bar ( galactic bars are still pretty mysterious) all embedded in a larger (diameter about 150,000 ly) oblate spheroidal halo of dark matter, globular clusters, and halo stars (very rare). 10. How big is our galaxy? How many stars ar ...
... diameter) disk of stars and gas and dust around a central bulge and bar ( galactic bars are still pretty mysterious) all embedded in a larger (diameter about 150,000 ly) oblate spheroidal halo of dark matter, globular clusters, and halo stars (very rare). 10. How big is our galaxy? How many stars ar ...
Student Handout - Mr. vallee`s Class Site
... and ________ moved through the sky in a different way than the stars. They noticed that, over time, these objects appeared to move with respect to the __________________________. 10. Because of the ___________________________ and its __________ around the Sun, it is convenient to divide the constell ...
... and ________ moved through the sky in a different way than the stars. They noticed that, over time, these objects appeared to move with respect to the __________________________. 10. Because of the ___________________________ and its __________ around the Sun, it is convenient to divide the constell ...
Second Semester Study Guide
... A. Because according to the nebular hypothesis, massive planets should only form away from their star. B. The density of these planets is very high. C. According to the nebular hypothesis, planets cannot be larger than Jupiter. D. The nebular hypothesis predicts that close in planets should have for ...
... A. Because according to the nebular hypothesis, massive planets should only form away from their star. B. The density of these planets is very high. C. According to the nebular hypothesis, planets cannot be larger than Jupiter. D. The nebular hypothesis predicts that close in planets should have for ...
Grade Nine Planetarium script
... Show how to use the pointer stars to find the little dipper, Cassiopeia, Cepheus, Cygnus, and Draco. b) Show how to measure angles with you fist (10 degrees) and finger (1 degree) at arms length. c) imagine pouring water out of the cup of the big dipper. follow the line of the pointer stars in that ...
... Show how to use the pointer stars to find the little dipper, Cassiopeia, Cepheus, Cygnus, and Draco. b) Show how to measure angles with you fist (10 degrees) and finger (1 degree) at arms length. c) imagine pouring water out of the cup of the big dipper. follow the line of the pointer stars in that ...
Origin of the Chemical Elements
... and radiation at smaller length scale. The inflationary period in the evolution of the Universe ended at about 10−32 s after the Big Bang. At this moment the constant ordered potential energy density driving the inflation decayed into the particles observed today. Some of them may have belonged to a ...
... and radiation at smaller length scale. The inflationary period in the evolution of the Universe ended at about 10−32 s after the Big Bang. At this moment the constant ordered potential energy density driving the inflation decayed into the particles observed today. Some of them may have belonged to a ...
Magnetized Gravitational Collapse & Star Formation
... Conjecture: Outflows break out when infall weakens and widens after center has accumulated some fraction (50%?) of core mass (1/3 of which is ejected in X-wind). Physical content of Class 0? (Andre, Ward-Thompson & Barsony 1993) Stellar mass is therefore defined by X-wind as 1/3 of core mass M 0 m ...
... Conjecture: Outflows break out when infall weakens and widens after center has accumulated some fraction (50%?) of core mass (1/3 of which is ejected in X-wind). Physical content of Class 0? (Andre, Ward-Thompson & Barsony 1993) Stellar mass is therefore defined by X-wind as 1/3 of core mass M 0 m ...
Collapse of an unstable Neutron Star to a Black Hole
... star merger process a new supramassive or hypermassive neutron star is formed, which could be stable for longer times or collapse almost immediately to a black hole. During this process a short gamma ray burst is emitted, releasing in less than one second the energy emitted by our Galaxy over one ye ...
... star merger process a new supramassive or hypermassive neutron star is formed, which could be stable for longer times or collapse almost immediately to a black hole. During this process a short gamma ray burst is emitted, releasing in less than one second the energy emitted by our Galaxy over one ye ...
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.