D1 Stellar quantities (PPT)
... Thus, in order to produce a helium nucleus, four hydrogen nuclei are used in total (six are used in the fusion reactions and two are generated). ...
... Thus, in order to produce a helium nucleus, four hydrogen nuclei are used in total (six are used in the fusion reactions and two are generated). ...
1 Stars
... For most of a star’s life, hydrogen atoms fuse to form helium atoms. A star like this is a main sequence star. The hotter a main sequence star is, the brighter it is. A star remains on the main sequence as long as it is fusing hydrogen to form helium. Our Sun has been a main sequence star for about ...
... For most of a star’s life, hydrogen atoms fuse to form helium atoms. A star like this is a main sequence star. The hotter a main sequence star is, the brighter it is. A star remains on the main sequence as long as it is fusing hydrogen to form helium. Our Sun has been a main sequence star for about ...
File - YEAR 11 EBSS PHYSICS DETAILED STUDIES
... But how is the mass turned into energy? This is done at the center, or core, of the sun, and is achieved through the process known as nuclear fusion. A nuclear fusion reaction occurs when two nuclei (hydrogen nuclei in the case of our sun) fuse together creating a new nucleus (helium), this re ...
... But how is the mass turned into energy? This is done at the center, or core, of the sun, and is achieved through the process known as nuclear fusion. A nuclear fusion reaction occurs when two nuclei (hydrogen nuclei in the case of our sun) fuse together creating a new nucleus (helium), this re ...
White Dwarfs - University of Maryland Astronomy
... Light waves take extra time to climb out of a deep hole in spacetime, leading to a gravitational redshift. ...
... Light waves take extra time to climb out of a deep hole in spacetime, leading to a gravitational redshift. ...
November 2013 - Pomona Valley Amateur Astronomers
... have surrounded the cluster of atoms since they rarely interact with matter. Eventually clusters of stars would appear. At the center of each cloud of stuff one large star would begin to accrete from its surroundings. The fusion of hydrogen into helium can permit very large stars to form before coll ...
... have surrounded the cluster of atoms since they rarely interact with matter. Eventually clusters of stars would appear. At the center of each cloud of stuff one large star would begin to accrete from its surroundings. The fusion of hydrogen into helium can permit very large stars to form before coll ...
Nucleosynthesis and the death of stars
... • A supernova is a massive explosion of a star that occurs under two possible scenarios. The first is that a white dwarf star undergoes a nuclear based explosion after it reaches its Chandrasekhar limit from absorbing mass from a neighboring star (usually a red giant). • The second, and more common, ...
... • A supernova is a massive explosion of a star that occurs under two possible scenarios. The first is that a white dwarf star undergoes a nuclear based explosion after it reaches its Chandrasekhar limit from absorbing mass from a neighboring star (usually a red giant). • The second, and more common, ...
NASAexplores 9-12 Lesson: Classified Stars - Science
... being the same distance away from the earth. On this diagram, you do not see all of the individual stars. Since there are so many stars, only a few were actually scattered around and along each of the areas that you see. The four major star types are white dwarf, main sequence, giant, and supergiant ...
... being the same distance away from the earth. On this diagram, you do not see all of the individual stars. Since there are so many stars, only a few were actually scattered around and along each of the areas that you see. The four major star types are white dwarf, main sequence, giant, and supergiant ...
Exploring the Universe
... 2. Main-Sequence Stars a. Main sequence: A line or sequence in an H-R diagram where most stars spend 90% of their life. i. A diagonal band running from the bright, hot stars on the upper left to the dim, cool stars on the lower right ii. Example: The Sun lies in the main sequence iii. The sun is a ...
... 2. Main-Sequence Stars a. Main sequence: A line or sequence in an H-R diagram where most stars spend 90% of their life. i. A diagonal band running from the bright, hot stars on the upper left to the dim, cool stars on the lower right ii. Example: The Sun lies in the main sequence iii. The sun is a ...
Star Birth: The Formation of Stars Jonathan Rowles
... A star is a luminous ball of gas. They produce energy by the nuclear fusion of hydrogen to form helium. They range in size from 0.08 times the mass of the Sun to up to 120 Solar masses. They can have lifetimes ranging from a few million years to the age of the universe. ...
... A star is a luminous ball of gas. They produce energy by the nuclear fusion of hydrogen to form helium. They range in size from 0.08 times the mass of the Sun to up to 120 Solar masses. They can have lifetimes ranging from a few million years to the age of the universe. ...
Energy - Monday Munchees
... massive a star, the more tightly its gravity pulls it together, the hotter it must be to keep it from collapsing, and the more rapidly it uses up its hydrogen fuel. The reason there are so few really massive stars is that they do not live very long, as little as a million years. For comparison, our ...
... massive a star, the more tightly its gravity pulls it together, the hotter it must be to keep it from collapsing, and the more rapidly it uses up its hydrogen fuel. The reason there are so few really massive stars is that they do not live very long, as little as a million years. For comparison, our ...
sc_examII_fall_2002 - University of Maryland
... A. a few hundred feet away. B. a few miles away. C. a few hundred miles away. ...
... A. a few hundred feet away. B. a few miles away. C. a few hundred miles away. ...
STELLAR STRUCTURE AND EVOLUTION
... Spectrum . . . yields information about surface chemical composition and gravity Evidence from: • Individual stars • Binary systems • Star clusters....these reveal how stars evolve with time • Nuclear physics...energy source, synthesis of heavy elements No direct information about physical condition ...
... Spectrum . . . yields information about surface chemical composition and gravity Evidence from: • Individual stars • Binary systems • Star clusters....these reveal how stars evolve with time • Nuclear physics...energy source, synthesis of heavy elements No direct information about physical condition ...
The HR Diagram (PowerPoint version)
... Unfortunately, You and I Have Been Scooped This correlation between ...
... Unfortunately, You and I Have Been Scooped This correlation between ...
Black Holes S.Chandrasekhar (1910-1995) March 27
... Maximum mass of a white dwarf • Chandrasekhar limit = 1.4 solar masses • Beyond that mass, the degenerate electrons cannot balance gravity and the white dwarf would collapse ...
... Maximum mass of a white dwarf • Chandrasekhar limit = 1.4 solar masses • Beyond that mass, the degenerate electrons cannot balance gravity and the white dwarf would collapse ...
15.2 Characteristics of Stars
... • Because distances in the universe are so large, astronomers use units other than meters to measure distances. • Two units of measure that astronomers use are astronomical units and light-years. • One astronomical unit (1 AU) is equal to the average distance the Sun is from the Earth or 93 million ...
... • Because distances in the universe are so large, astronomers use units other than meters to measure distances. • Two units of measure that astronomers use are astronomical units and light-years. • One astronomical unit (1 AU) is equal to the average distance the Sun is from the Earth or 93 million ...
Stars, Galaxies & Universe
... If given a protostar, what is the next likely stage of the star? Super Giant Nova Main Sequence Neutron Star ...
... If given a protostar, what is the next likely stage of the star? Super Giant Nova Main Sequence Neutron Star ...
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.