THE GALACTIC GAZETTE The Astronomical Society of Southern New England Next Meeting
... The simulations revealed that a supermassive star burns hydrogen at a furious rate for under 2 million years—a mere blink of a cosmic eye (the Sun is about 5 billion years old) before beginning to collapse. Then what happens internally depends critically on its mass. If it is less than 55,000 or mor ...
... The simulations revealed that a supermassive star burns hydrogen at a furious rate for under 2 million years—a mere blink of a cosmic eye (the Sun is about 5 billion years old) before beginning to collapse. Then what happens internally depends critically on its mass. If it is less than 55,000 or mor ...
Stars - gilbertmath.com
... The material falling inward to the _________ has excess ________________ that causes the central ball of material to begin to ________________. Extremely high _________________ build up inside the ball, which in turn causes tightly packed ___________ to heat up. As the ____________________ clim ...
... The material falling inward to the _________ has excess ________________ that causes the central ball of material to begin to ________________. Extremely high _________________ build up inside the ball, which in turn causes tightly packed ___________ to heat up. As the ____________________ clim ...
A) Polaris B) Betelgeuse C) Procyon B D) Sirius 1. Which star has a
... A) in the Sun by fusion B) when water condenses in Earth's atmosphere C) from the movement of crustal plates D) during nuclear decay 23. Base your answer to the following question on the diagram below, which shows an inferred sequence in which our solar system formed from a giant interstellar cloud ...
... A) in the Sun by fusion B) when water condenses in Earth's atmosphere C) from the movement of crustal plates D) during nuclear decay 23. Base your answer to the following question on the diagram below, which shows an inferred sequence in which our solar system formed from a giant interstellar cloud ...
Likely formation of general relativistic radiation pressure supported
... radiating object is supposed to attain the black hole (BH) stage having z = ∞. As the collapse/contraction proceeds, both M and R decrease so that z increases and eventually, the collapsing body must approach the exact BH state with z = ∞. The effect of radiation trapping during these intermediate h ...
... radiating object is supposed to attain the black hole (BH) stage having z = ∞. As the collapse/contraction proceeds, both M and R decrease so that z increases and eventually, the collapsing body must approach the exact BH state with z = ∞. The effect of radiation trapping during these intermediate h ...
Star
... • Massive stars become supernovas as part of their life cycle. • After the supergiant stage, the star collapses, producing such high temperatures that nuclear fusion begins again. • When nuclear fusion stops, the star’s core begins to collapse under its own gravity. This causes the outer layers to e ...
... • Massive stars become supernovas as part of their life cycle. • After the supergiant stage, the star collapses, producing such high temperatures that nuclear fusion begins again. • When nuclear fusion stops, the star’s core begins to collapse under its own gravity. This causes the outer layers to e ...
Determining the Sizes of Stars Using the HR Diagram
... massive than the Sun while the least massive ones are only 0.08 times the mass of the Sun. Most stars spend about 90% of their lifetimes shining due to nuclear fusion that goes on in their cores, but after awhile they evolve and begin to die. How long they live and what they evolve to become when th ...
... massive than the Sun while the least massive ones are only 0.08 times the mass of the Sun. Most stars spend about 90% of their lifetimes shining due to nuclear fusion that goes on in their cores, but after awhile they evolve and begin to die. How long they live and what they evolve to become when th ...
Chandra Observation of Pulsar Wind Nebula
... • The morphology of a PWN is determined by the interaction with the environment. If the pulsar – is in a low density cavity, then the structure of the PWN reflects mainly the pulsar wind geometry. – is surrounded by the SNR ejecta, the wind materials will be well confined, and the expansion of the P ...
... • The morphology of a PWN is determined by the interaction with the environment. If the pulsar – is in a low density cavity, then the structure of the PWN reflects mainly the pulsar wind geometry. – is surrounded by the SNR ejecta, the wind materials will be well confined, and the expansion of the P ...
Stellar Evolution
... • all the stars are at about the same distance from the Earth • all the stars formed at about the same time Determining the distance and age to a globular cluster is much easier than trying to find the distances and ages of a million random stars! Laboratories for understanding how stars of differen ...
... • all the stars are at about the same distance from the Earth • all the stars formed at about the same time Determining the distance and age to a globular cluster is much easier than trying to find the distances and ages of a million random stars! Laboratories for understanding how stars of differen ...
Frank Timmes (ASU)
... 1. SN Ia 2011fe (M101) discovered by the Palomar Transient Factory about 11 hours after the explosion. No evidence for circumbinary material and progenitor likely a CO WD. 2. However, PTF 11kx was a SN Ia that exploded in a system with circumbinary material and they suggest that the progenitor was a ...
... 1. SN Ia 2011fe (M101) discovered by the Palomar Transient Factory about 11 hours after the explosion. No evidence for circumbinary material and progenitor likely a CO WD. 2. However, PTF 11kx was a SN Ia that exploded in a system with circumbinary material and they suggest that the progenitor was a ...
Stellar Evolution Nucleosynthesis
... Dead Stars leave corpses • White dwarfs – remnant core of low mass star – supported by electron degeneracy pressure ...
... Dead Stars leave corpses • White dwarfs – remnant core of low mass star – supported by electron degeneracy pressure ...
Announcements
... Weight of the outer layers exerts a huge force pushing down on the deeper layers. So why doesn’t the sun collapse all the way? ...
... Weight of the outer layers exerts a huge force pushing down on the deeper layers. So why doesn’t the sun collapse all the way? ...
Stars as thermonuclear reactors: their fuels and ashes
... the Big Bang, contains many more photons per particle of matter with mass, e.g. electrons, protons and neutrons. Because of the high entropy and the consequent low density of matter (on terrestrial or stellar scales) at any given temperature as the universe expanded, there was time to manufacture el ...
... the Big Bang, contains many more photons per particle of matter with mass, e.g. electrons, protons and neutrons. Because of the high entropy and the consequent low density of matter (on terrestrial or stellar scales) at any given temperature as the universe expanded, there was time to manufacture el ...
2-star-life-cycle-and-star-classification
... A) in the Sun by fusion B) when water condenses in Earth's atmosphere C) from the movement of crustal plates D) during nuclear decay 23. Base your answer to the following question on the diagram below, which shows an inferred sequence in which our solar system formed from a giant interstellar cloud ...
... A) in the Sun by fusion B) when water condenses in Earth's atmosphere C) from the movement of crustal plates D) during nuclear decay 23. Base your answer to the following question on the diagram below, which shows an inferred sequence in which our solar system formed from a giant interstellar cloud ...
Astronomy 252: Short Project 2 Stellar Spectra: Their Classification
... stars in the sky have temperatures in excess of 40,000 K, whereas the coolest stars that we can detect optically have temperatures on the order of 2000 - 3000 K. As you might guess, the appearance of the spectrum of a star is very strongly dependent on its temperature. For instance the very hottest ...
... stars in the sky have temperatures in excess of 40,000 K, whereas the coolest stars that we can detect optically have temperatures on the order of 2000 - 3000 K. As you might guess, the appearance of the spectrum of a star is very strongly dependent on its temperature. For instance the very hottest ...
arXiv:hep-ph/9910471 25 Oct 1999
... matter (109 erg cm−3 or ∼ 0.1 eV per molecular bond). At a mass above 1.5 ng, for a typical nuclear density, the object becomes larger than an atom and the positron cloud that it has been developing sits mainly inside the strangelet itself (for stable strangelets that have grown this large, the sign ...
... matter (109 erg cm−3 or ∼ 0.1 eV per molecular bond). At a mass above 1.5 ng, for a typical nuclear density, the object becomes larger than an atom and the positron cloud that it has been developing sits mainly inside the strangelet itself (for stable strangelets that have grown this large, the sign ...
7 November 2012 X-ray Astrophysics
... plasma) will show many such emission lines, each one indicative of a unique transition of an electron between two energy levels in an element. Thus detailed study and modelling of the emission line spectrum of a source will reveal much about its chemical composition to astronomers. A similar process ...
... plasma) will show many such emission lines, each one indicative of a unique transition of an electron between two energy levels in an element. Thus detailed study and modelling of the emission line spectrum of a source will reveal much about its chemical composition to astronomers. A similar process ...
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.