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 ...
Radial Stellar Pulsations
... Effect (i) is always destabilizing because the nuclear reaction rate increases with increasing temperature and pressure: thus the change in reaction rate tends to add entropy to the core when it is at higher than equilibrium temperature. Except in very massive stars (& 100 M⊙), the epsilon mechanism ...
... Effect (i) is always destabilizing because the nuclear reaction rate increases with increasing temperature and pressure: thus the change in reaction rate tends to add entropy to the core when it is at higher than equilibrium temperature. Except in very massive stars (& 100 M⊙), the epsilon mechanism ...
Measuring Distance with Spectroscopic Parallax
... 1. Print out the HR diagram. 2. Using a pen or pencil, draw a smooth best-fit curve that runs through the middle of all of your main sequence stars. Just ignore the red giants and white dwarfs for this activity. Note that this will not be a straight line; it will curve slightly. And, it will not go ...
... 1. Print out the HR diagram. 2. Using a pen or pencil, draw a smooth best-fit curve that runs through the middle of all of your main sequence stars. Just ignore the red giants and white dwarfs for this activity. Note that this will not be a straight line; it will curve slightly. And, it will not go ...
Stars in Their Youth
... is that they are converting hydrogen into helium in their cores. In the Chap. 1 we outlined the extraordinary conjecture by Eddington. But it took nearly twenty years to work out the details. The first breakthrough in solving the problem of how stars liberate energy came in 1938 when C. F. von Weizs ...
... is that they are converting hydrogen into helium in their cores. In the Chap. 1 we outlined the extraordinary conjecture by Eddington. But it took nearly twenty years to work out the details. The first breakthrough in solving the problem of how stars liberate energy came in 1938 when C. F. von Weizs ...
Astronomy Worksheet
... Write the calculated temperature on your graph. Show the set-up your calculation. 4. Use the above chart to estimate the color of your star. Write the color on the graph. 5. Often absorption lines will present as broad, V-shaped notches, in some cases 50 A or more. These are often caused by molecula ...
... Write the calculated temperature on your graph. Show the set-up your calculation. 4. Use the above chart to estimate the color of your star. Write the color on the graph. 5. Often absorption lines will present as broad, V-shaped notches, in some cases 50 A or more. These are often caused by molecula ...
Science Olympiad Astronomy C Division Event Golden Gate
... 5. Order images 3, 7, 14, 18, 23 from largest to smallest in physical size. 6. Refer to Image 29 (for locations use letter that best represents the object asked about): What is the name of this diagram? a. Where (what letter A – O) is the bright object in image 1? b. Where (what letter A – O) is the ...
... 5. Order images 3, 7, 14, 18, 23 from largest to smallest in physical size. 6. Refer to Image 29 (for locations use letter that best represents the object asked about): What is the name of this diagram? a. Where (what letter A – O) is the bright object in image 1? b. Where (what letter A – O) is the ...
Lecture
... – O star: ~ 1 million years – G star (Sun): ~ 10 billion years – M star : ~ 5,000 billion years ...
... – O star: ~ 1 million years – G star (Sun): ~ 10 billion years – M star : ~ 5,000 billion years ...
Nuclear Physics
... stars must be thermonuclear fusion reactions. In these reactions, lighter elements burn to form heavier elements =⇒ nucleosynthesis. 2. Two nuclei will fuse to form one nuclei if they come within 10−13 cm of each other — but they must be moving fast enough to overcome the Coulomb repulsion that exis ...
... stars must be thermonuclear fusion reactions. In these reactions, lighter elements burn to form heavier elements =⇒ nucleosynthesis. 2. Two nuclei will fuse to form one nuclei if they come within 10−13 cm of each other — but they must be moving fast enough to overcome the Coulomb repulsion that exis ...
Solutions - Yale Astronomy
... electromagnetic spectrum. Stars behave as blackbodies thus, despite peaking in the UV, it emits light at all wavelengths. The amount of flux a star emits is directly proportional to T4 , thus for a star with a high surface temperature will also emit more flux at all wavelengths than a similar star w ...
... electromagnetic spectrum. Stars behave as blackbodies thus, despite peaking in the UV, it emits light at all wavelengths. The amount of flux a star emits is directly proportional to T4 , thus for a star with a high surface temperature will also emit more flux at all wavelengths than a similar star w ...
Building the Hertzsprung
... What would be the lifetime of a star one tenth as massive as our sun? A: 1 billion years = 109 years B: 10 billion years = 1010 years C: 100 billion years = 1011 years D: 1 trillion years = 1012 years ...
... What would be the lifetime of a star one tenth as massive as our sun? A: 1 billion years = 109 years B: 10 billion years = 1010 years C: 100 billion years = 1011 years D: 1 trillion years = 1012 years ...
Chandra Sees the Atmosphere of a Neutron Star - Chandra X
... star is only 14 miles (23 kilometers) in diameter, and is as dense as an atomic nucleus (100 trillion gm/cc). The atmosphere is only about four inches (10 cm) thick, has a density similar to diamond (3.5 gm/cc), and a temperature of nearly 2 million Kelvin. The surface gravity on the neutron star is ...
... star is only 14 miles (23 kilometers) in diameter, and is as dense as an atomic nucleus (100 trillion gm/cc). The atmosphere is only about four inches (10 cm) thick, has a density similar to diamond (3.5 gm/cc), and a temperature of nearly 2 million Kelvin. The surface gravity on the neutron star is ...
Globular Clusters Dynamic Lives The
... integrated star clusters along with some dwarf satellite galaxies. The 150 or so globulars surviving today are probably just a small fraction of those that once populated the galactic halo. Tidal shocks can also accelerate the evolution of clusters toward core collapse. Whether a cluster will evapor ...
... integrated star clusters along with some dwarf satellite galaxies. The 150 or so globulars surviving today are probably just a small fraction of those that once populated the galactic halo. Tidal shocks can also accelerate the evolution of clusters toward core collapse. Whether a cluster will evapor ...
1 How luminous are stars?
... We measure mass using gravity Direct mass measurements are possible only for stars in binary star systems ...
... We measure mass using gravity Direct mass measurements are possible only for stars in binary star systems ...
Exam 03
... A) Because the interstellar medium is predominantly hydrogen, the H-α line makes stars all appear red. B) When viewed through a cloud of interstellar gas and dust,a star will appear redder than it actually is. The blue light it emits will be scattered more by the cloud than the red light will be. C) ...
... A) Because the interstellar medium is predominantly hydrogen, the H-α line makes stars all appear red. B) When viewed through a cloud of interstellar gas and dust,a star will appear redder than it actually is. The blue light it emits will be scattered more by the cloud than the red light will be. C) ...
Emission and Absorption Spectra
... C. the peak of star A’s spectrum would be at a shorter wavelength than star B and it would be redder D. the peak of star A’s spectrum would be at a longer wavelength than star B and it would be bluer E. the peak of star A’s spectrum would be at a longer wavelength than star B, but they would both ap ...
... C. the peak of star A’s spectrum would be at a shorter wavelength than star B and it would be redder D. the peak of star A’s spectrum would be at a longer wavelength than star B and it would be bluer E. the peak of star A’s spectrum would be at a longer wavelength than star B, but they would both ap ...
AyC10 Fall 2007: Midterm 2 Review Sheet
... parallax or other methods we haven’t discussed in detail). Once we know those two quantities, we use the equation b = L / 4d2 to compute the luminosity. CS 160-168 What does it mean for a star to be on the Main Sequence? A star is on the Main Sequence when its core is fusing hydrogen into helium. D ...
... parallax or other methods we haven’t discussed in detail). Once we know those two quantities, we use the equation b = L / 4d2 to compute the luminosity. CS 160-168 What does it mean for a star to be on the Main Sequence? A star is on the Main Sequence when its core is fusing hydrogen into helium. D ...
LIFE CYCLE OF STARS
... to its gravity. As the pressure and temperature increase, the new star begins nuclear fusion. As the new star equalizes in pressure and gravity, it becomes a star (its next stage of life). Vocabulary: Nebula-A diffuse mass of interstellar dust and gas. Protostar-Very dense regions (or cores) of mole ...
... to its gravity. As the pressure and temperature increase, the new star begins nuclear fusion. As the new star equalizes in pressure and gravity, it becomes a star (its next stage of life). Vocabulary: Nebula-A diffuse mass of interstellar dust and gas. Protostar-Very dense regions (or cores) of mole ...
The Milky Way * A Classic Galaxy
... • Pop I: stars with metals, formed only after many supernovae enriched the interstellar medium and interstellar clouds with metals • Pop II, metal-poor stars, all in the bulge and halo • Pop I,II show MW formed spheroid first, then disk more gradually. • Hubble discovered Cepheids in Andromeda Nebul ...
... • Pop I: stars with metals, formed only after many supernovae enriched the interstellar medium and interstellar clouds with metals • Pop II, metal-poor stars, all in the bulge and halo • Pop I,II show MW formed spheroid first, then disk more gradually. • Hubble discovered Cepheids in Andromeda Nebul ...
Astro 10B Study Questions for Each Chapter
... How are galaxies, groups and clusters distributed through space? Which type of clusters contain the most giant elliptical galaxies? Where would you find a galaxy which is the result of several mergers? What happens when galaxies collide? How would you explain a galaxy having multiple nuclei? Why do ...
... How are galaxies, groups and clusters distributed through space? Which type of clusters contain the most giant elliptical galaxies? Where would you find a galaxy which is the result of several mergers? What happens when galaxies collide? How would you explain a galaxy having multiple nuclei? Why do ...
File - We All Love Science
... What are the general properties of White Dwarfs? • Chandrasekar Limit – 1931, Indian astrophysicist Subrahmanyan Chandrasekhar (who was only age 21!) – He later won the Nobel Prize – The limit to how large a white dwarf can be before it collapses is about 1.4 M☉ ...
... What are the general properties of White Dwarfs? • Chandrasekar Limit – 1931, Indian astrophysicist Subrahmanyan Chandrasekhar (who was only age 21!) – He later won the Nobel Prize – The limit to how large a white dwarf can be before it collapses is about 1.4 M☉ ...
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.