Today in Astronomy 102: electron degeneracy pressure and white
... Theory of white dwarfs Fowler applied his theory of degeneracy pressure, soon after he invented it (1926), to white dwarf stars. His result: q Stars supported by degeneracy pressure instead of gas pressure would have sizes close to that determined from astronomical observations of Sirius B. Soon th ...
... Theory of white dwarfs Fowler applied his theory of degeneracy pressure, soon after he invented it (1926), to white dwarf stars. His result: q Stars supported by degeneracy pressure instead of gas pressure would have sizes close to that determined from astronomical observations of Sirius B. Soon th ...
EvoluGon of high mass stars Solar-‐type stars end their lives by
... envelope of the star is driven off. As the envelope becomes op=cally thin the light from the hot interior escapes and the object brightens drama=cally. The star has now become a supernova. The image ...
... envelope of the star is driven off. As the envelope becomes op=cally thin the light from the hot interior escapes and the object brightens drama=cally. The star has now become a supernova. The image ...
Chapter 14 Our Star The Sun is the Largest Object in the Solar
... The annual change in numbers of sunspots reveals that the Sun experiences an 11-year Sun Spot cycle ...
... The annual change in numbers of sunspots reveals that the Sun experiences an 11-year Sun Spot cycle ...
Lecture 5
... In hydrostatic equilibrium no net force acting on gas (i.e. gravity balanced by pressure) Consider a slab of gas area A, thickness r Force due to gravity Fg, is given by ...
... In hydrostatic equilibrium no net force acting on gas (i.e. gravity balanced by pressure) Consider a slab of gas area A, thickness r Force due to gravity Fg, is given by ...
Science Olympiad 2008 Reach for the Stars Division B
... B) Less than one solar mass C) around 1 solar mass D) 1 to 3 solar masses E) More than 3 solar masses 95. Suppose that Betelgeuse were to become a supernova and be observed from Earth. What would it look like to the naked eye? A) Because the supernova event destroys the star, Betelgeuse would sudden ...
... B) Less than one solar mass C) around 1 solar mass D) 1 to 3 solar masses E) More than 3 solar masses 95. Suppose that Betelgeuse were to become a supernova and be observed from Earth. What would it look like to the naked eye? A) Because the supernova event destroys the star, Betelgeuse would sudden ...
Page 1 of 4 KEY PSCI 1055 Test #4 (Form A) KEY Spring 2008
... b. What type of star has the lowest temperature but the highest level of brightness on the H-R diagram? giants/supergiants c. A particular star has an absolute magnitude of 2.5. What type(s) of star could this star be? main sequence or giant d. Suppose the star in part c is also found to have a temp ...
... b. What type of star has the lowest temperature but the highest level of brightness on the H-R diagram? giants/supergiants c. A particular star has an absolute magnitude of 2.5. What type(s) of star could this star be? main sequence or giant d. Suppose the star in part c is also found to have a temp ...
Surveys of Stars, The interstellar medium
... - White Dwarfs are hot but since they are so small, they are not very luminous. ...
... - White Dwarfs are hot but since they are so small, they are not very luminous. ...
Reach for the Stars – Div. B
... • Electron transition from a lower energy state to a higher energy state receiving energy adsorption line • Electron transition from a higher energy state to a lower energy state giving off energy emission line • Below is the Balmer series of lines associated with electron transition in the ...
... • Electron transition from a lower energy state to a higher energy state receiving energy adsorption line • Electron transition from a higher energy state to a lower energy state giving off energy emission line • Below is the Balmer series of lines associated with electron transition in the ...
ASTR 553/554 (1) : Questions
... luminous because they're intrinsically luminous per kg -- indeed they are quite feeble in that sense. They are luminous only because their furnaces are so massive. b. To emphasize this, estimate your own M/Lbol ratio, using the same units. Assume you weigh 100 kg and radiate like a black body of ar ...
... luminous because they're intrinsically luminous per kg -- indeed they are quite feeble in that sense. They are luminous only because their furnaces are so massive. b. To emphasize this, estimate your own M/Lbol ratio, using the same units. Assume you weigh 100 kg and radiate like a black body of ar ...
Unit 2-1 Life Cycle of the Sun
... The purpose of this activity is to have you observe the changes in the temperature, absolute magnitude, and other observable characteristics of two different types of stars as they go through their life cycles. The absolute magnitude is a measure of how bright a star would appear if it was approxima ...
... The purpose of this activity is to have you observe the changes in the temperature, absolute magnitude, and other observable characteristics of two different types of stars as they go through their life cycles. The absolute magnitude is a measure of how bright a star would appear if it was approxima ...
Stars: some basic characteristics
... Since stars emit a thermal spectrum (at least approximately), by measuring the ratio of a star’s brightness at a blue wavelength and a redder wavelength, we can estimate it’s temperature. ...
... Since stars emit a thermal spectrum (at least approximately), by measuring the ratio of a star’s brightness at a blue wavelength and a redder wavelength, we can estimate it’s temperature. ...
AST 301 Introduction to Astronomy - University of Texas Astronomy
... The flux of a star is the power in the light from that star that would hit a 1 m2 area facing the star. To measure a star’s flux, we use a telescope to collect light from the star, measure the power in the light we collect, and the divide the power by the collecting area of the telescope. (A bigger ...
... The flux of a star is the power in the light from that star that would hit a 1 m2 area facing the star. To measure a star’s flux, we use a telescope to collect light from the star, measure the power in the light we collect, and the divide the power by the collecting area of the telescope. (A bigger ...
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.