The Sun
... • It pays to look at this paradox from another direction. – The sun is an average star, and there are billions like it in the sky. – The more astronomers can learn from the convenient example of the sun, the more they will know about other stars, whose distances from Earth render detailed study impo ...
... • It pays to look at this paradox from another direction. – The sun is an average star, and there are billions like it in the sky. – The more astronomers can learn from the convenient example of the sun, the more they will know about other stars, whose distances from Earth render detailed study impo ...
Homework extension
... “squashed” up and the frequency will increase and the wavelength decrease. This is often called blue shift. There is an observed increase in the wavelength of light from most galaxies, this is evidence that galaxies are moving away from us, and supports the big bang theory, that the universe began f ...
... “squashed” up and the frequency will increase and the wavelength decrease. This is often called blue shift. There is an observed increase in the wavelength of light from most galaxies, this is evidence that galaxies are moving away from us, and supports the big bang theory, that the universe began f ...
Introduction_to_pulsar_astronomy
... Radio emission from the Crab nebula was first detected by Bolton, Stanley and Slee (1949). It is one of the most powerful radio sources known, with a flux of 1000 Jy at 1 GHz. Apart from M1, it is also known as Taurus A, 3C144 and G184.6-5.8. The Crab nebula was the first known extra-solar X-ray sou ...
... Radio emission from the Crab nebula was first detected by Bolton, Stanley and Slee (1949). It is one of the most powerful radio sources known, with a flux of 1000 Jy at 1 GHz. Apart from M1, it is also known as Taurus A, 3C144 and G184.6-5.8. The Crab nebula was the first known extra-solar X-ray sou ...
Classification of Variable Stars
... three letter constellation abbreviation. There are also variables with names such as V746 Oph and V1668 Cyg. These are stars in constellations for which all of the letter combinations have been exhausted. (i.e. V746 Oph is the 746th variable to be discovered in Ophiuchus.) Variable star names are de ...
... three letter constellation abbreviation. There are also variables with names such as V746 Oph and V1668 Cyg. These are stars in constellations for which all of the letter combinations have been exhausted. (i.e. V746 Oph is the 746th variable to be discovered in Ophiuchus.) Variable star names are de ...
CPW
... • B is correct over A because like charges do in fact repel, not a^ract each other. If you did not know that like charges repel, you sAll could have go^en B over A, since if it were ...
... • B is correct over A because like charges do in fact repel, not a^ract each other. If you did not know that like charges repel, you sAll could have go^en B over A, since if it were ...
arXiv:astro-ph/9701131v1 18 Jan 1997
... of composition gradients which are ultimately responsible (in part) for a star’s ascent up the red giant branch. The lowest mass stars burn all their hydrogen into helium over an η = 13 time scale, and then quietly fade from prominence as helium white dwarfs. This general evolutionary scenario is de ...
... of composition gradients which are ultimately responsible (in part) for a star’s ascent up the red giant branch. The lowest mass stars burn all their hydrogen into helium over an η = 13 time scale, and then quietly fade from prominence as helium white dwarfs. This general evolutionary scenario is de ...
Chapter 12
... to stars. Parallax is a change in an object’s apparent position caused by a change in the observer’s position. An example—easy to demonstrate in your room—is to hold your hand motionless at arm’s length and shift your head from side to side. Your hand seems to move against the background even though ...
... to stars. Parallax is a change in an object’s apparent position caused by a change in the observer’s position. An example—easy to demonstrate in your room—is to hold your hand motionless at arm’s length and shift your head from side to side. Your hand seems to move against the background even though ...
Gamma Ray Burst Afterglows and Host Galaxies
... Deaths of Massive Stars Afterglow data suggests that GRBs occur… • in galaxies with active star formation, • often in regions with a lot of gas, which is where new stars form and where the most massive stars spend their entire brief lives. However, GRBs are so rare that only a tiny fraction of massi ...
... Deaths of Massive Stars Afterglow data suggests that GRBs occur… • in galaxies with active star formation, • often in regions with a lot of gas, which is where new stars form and where the most massive stars spend their entire brief lives. However, GRBs are so rare that only a tiny fraction of massi ...
The Evolution of Isotope Ratios in the Milky Way Galaxy
... metals are produced. This assumption may not be valid but does not affect the average chemical evolution of galaxies. Super AGB stars — The fate of stars with initial masses between about 8 − 10M⊙ is uncertain. The upper limit of AGB stars, Mu,1 , is defined as the minimum mass for carbon ignition, ...
... metals are produced. This assumption may not be valid but does not affect the average chemical evolution of galaxies. Super AGB stars — The fate of stars with initial masses between about 8 − 10M⊙ is uncertain. The upper limit of AGB stars, Mu,1 , is defined as the minimum mass for carbon ignition, ...
Red supergiants and the past of Cygnus OB2
... supergiants abound, indicating that many stars in the association have already evolved away from the main sequence and that the main star-forming sites have been shifting with time. The study of this older component is made difficult by the effects of stellar evolution, and in particular by the fact ...
... supergiants abound, indicating that many stars in the association have already evolved away from the main sequence and that the main star-forming sites have been shifting with time. The study of this older component is made difficult by the effects of stellar evolution, and in particular by the fact ...
12C13C1414N21312C/13C3he43He/4He Sub-surface
... Z=0.02 demonstrates that the FeCZ becomes more prominent for higher luminosity. This is because the opacity is not substantially changing among main sequence models at the same metallicity, such that a higher luminosity renders a larger portion of the envelope convectively unstable (both in radius a ...
... Z=0.02 demonstrates that the FeCZ becomes more prominent for higher luminosity. This is because the opacity is not substantially changing among main sequence models at the same metallicity, such that a higher luminosity renders a larger portion of the envelope convectively unstable (both in radius a ...
Homologous Stars: Simple Scaling Relations
... needed to express the structure in physical units, like c.g.s. For example, the two parameter may be K (which is related to entropy) and central density; or stellar mass and stellar radius; or K and the stellar mass; and so on. If we know the numerical or analytical solution of the Lane-Emden equati ...
... needed to express the structure in physical units, like c.g.s. For example, the two parameter may be K (which is related to entropy) and central density; or stellar mass and stellar radius; or K and the stellar mass; and so on. If we know the numerical or analytical solution of the Lane-Emden equati ...
an introduction to astrophysics
... In order to successfully study one or both of the Open University’s Level 3 courses, S382 Astrophysics or S383 The Relativistic Universe, you should already be familiar with various topics in cosmology, astronomy, planetary science, physics and mathematics. The level of skills, knowledge and underst ...
... In order to successfully study one or both of the Open University’s Level 3 courses, S382 Astrophysics or S383 The Relativistic Universe, you should already be familiar with various topics in cosmology, astronomy, planetary science, physics and mathematics. The level of skills, knowledge and underst ...
Here
... This work would not have been possible without the help and support of many people. I would like to take this opportunity to offer my thanks. First and foremost I would like to thank Chris for supervising me through the past three year. I have learnt much from him in this time, from the details of s ...
... This work would not have been possible without the help and support of many people. I would like to take this opportunity to offer my thanks. First and foremost I would like to thank Chris for supervising me through the past three year. I have learnt much from him in this time, from the details of s ...
White Paper on Nuclear Astrophysics
... stars. Others have only been raised more recently, driven by new results or observations, such as the origin of the elements in the Sr - Te range, the nature of the first stars, the mechanism to explode super X-ray bursts, or the contribution of proton rich neutrino driven winds or intermediate neut ...
... stars. Others have only been raised more recently, driven by new results or observations, such as the origin of the elements in the Sr - Te range, the nature of the first stars, the mechanism to explode super X-ray bursts, or the contribution of proton rich neutrino driven winds or intermediate neut ...
Luminosity, Flux and Magnitudes Outline
... by the microscopic motions of particles. There is a continuum of energy levels associated with this motion. If the object is in thermal equilibrium then it can be characterized by a single quantity, it’s temperature. An object in thermal equilibrium emits energy at all wavelengths. ...
... by the microscopic motions of particles. There is a continuum of energy levels associated with this motion. If the object is in thermal equilibrium then it can be characterized by a single quantity, it’s temperature. An object in thermal equilibrium emits energy at all wavelengths. ...
WHAT MAKES A STAR SO SPECIAL Abstract
... luminosity, or 1000 red stars from class M with low luminosity. This statistics shows that the formation of stars with low masses is a very common process. If we plot the spectral classes (or the temperature, which is the same) along the x-axis and the luminosity (or stars’ absolute magnitude) along ...
... luminosity, or 1000 red stars from class M with low luminosity. This statistics shows that the formation of stars with low masses is a very common process. If we plot the spectral classes (or the temperature, which is the same) along the x-axis and the luminosity (or stars’ absolute magnitude) along ...
The physics of star formation
... Stars are the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. They also serve as our primary tracers of the structure and evolution of the universe and its contents. Consequently, it is of central imp ...
... Stars are the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. They also serve as our primary tracers of the structure and evolution of the universe and its contents. Consequently, it is of central imp ...
The physics of star formation - Yale Astronomy
... Stars are the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. They also serve as our primary tracers of the structure and evolution of the universe and its contents. Consequently, it is of central imp ...
... Stars are the fundamental units of luminous matter in the universe, and they are responsible, directly or indirectly, for most of what we see when we observe it. They also serve as our primary tracers of the structure and evolution of the universe and its contents. Consequently, it is of central imp ...
The physics of star formation
... of their high opacity, the rate at which they are heated by external radiation is low; the result is that molecular clouds are very cold and have typical temperatures of only about 10–20 K. Higher temperatures of up to 100 K or more may exist locally in regions heated by luminous newly formed stars. ...
... of their high opacity, the rate at which they are heated by external radiation is low; the result is that molecular clouds are very cold and have typical temperatures of only about 10–20 K. Higher temperatures of up to 100 K or more may exist locally in regions heated by luminous newly formed stars. ...
Bez nadpisu
... to the luminosity of the system than afterward, when it is exhausted. The heights of the maxima in the pre-outburst state are different because we view the region where the stream and the outer parts of the disk interact from different angles. On the other hand, the depths of the minima are differen ...
... to the luminosity of the system than afterward, when it is exhausted. The heights of the maxima in the pre-outburst state are different because we view the region where the stream and the outer parts of the disk interact from different angles. On the other hand, the depths of the minima are differen ...
a changing cosmos - Whittier Union High School District
... and not really able to affect things around us much. But there are some types of events in our changing cosmos that could really mess things up badly for us. In fossil records, there are many instances of species going extinct—apparently unable to cope with some change in environment. At certain tim ...
... and not really able to affect things around us much. But there are some types of events in our changing cosmos that could really mess things up badly for us. In fossil records, there are many instances of species going extinct—apparently unable to cope with some change in environment. At certain tim ...
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.