Neutrinos have never been detected experimentally. (T/F)
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A: Gamma rays are the photons with the highest energy ever detected. Gamma-ray bursts or GRBS are…
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Q: The proton-proton chain releases energy because mass is cre- ated in the process. (T/F)
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Q: Why does helium fusion require a higher temperature than hydrogen fusion?
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Q: The most abundant element in the Sun is hydrogen. (T/F)
A: Sun is the star at the center of our solar system. It belongs to the G-type main-sequence stars.…
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Q: What is 21-cm radiation? With what element is it associated? Why is it useful to astronomers?
A: Radiations are the transmission and emission of energies in the form of particles and waves through…
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Q: Given that the solar spectrum corresponds to a temperature of 5800 K and peaks at a wavelength of…
A: A blackbody is an object that is capable of absorbing all the radiation that falls on it. Black-body…
Q: a)What type of supernova is most luminous in light? (b) What kind of star results in such an…
A: a) Supernova is an astronomical event take place when a white dwarf star exploded. When the white…
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Q: Given a low density cloud of Hydrogen atoms, what happens when the temperature of the cloud is…
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A: Given :- angular diameter of radio source = 0.0024 arc seconds. distance = 2.30 Mpc .
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A: Given, The wavelength of the emission line λ=21 cm = 0.21 m The speed of light, c=3×108 m/s Take,…
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- A main sequence star of mass 25 M⊙has a luminosity of approximately 80,000 L⊙. a. At what rate DOES MASS VANISH as H is fused to He in the star’s core? Note: When we say “mass vanish '' what we really mean is “gets converted into energy and leaves the star as light”. Note: approximate answer: 3.55 E14 kg/s b. At what rate is H converted into He? To do this you need to take into account that for every kg of hydrogen burned, only 0.7% gets converted into energy while the rest turns into helium. Approximate answer = 5E16 kg/s c. Assuming that only the 10% of the star’s mass in the central regions will get hot enough for fusion, calculate the main sequence lifetime of the star. Put your answer in years, and compare it to the lifetime of the Sun. It should be much, much shorter. Approximate answer: 30 million years.Flares are caused by magnetic disturbances in the lower atmo- sphere of the Sun. (T/F)P9 E4
- A supernova’s energy is often compared to the total energy output of the Sun over its lifetime. Using the Sun’s current luminosity, calculate the total solar energy output, assuming a 1010 year main-sequence lifetime. Using Einstein’s formula E=mc2 calculate the equivalent amount of mass, expressed in Earth masses. [Hint: The total energy output of the Sun over its lifetime is given by its current luminosity times the number of seconds in a year times its ten billion-year lifetime; ; mass of earth = 6×1024kg; c = 3×108m/s. Your answer should be 200-300 Earth masses.]if a star is converted every bit of its mass. into energy the conversion efficiency would be 100%. however no star is this efficient in its energy production stars with less than 1.3 solar masses convert hydrogen into helium with an efficiency of only 0.7%. besring in mind that aldebaram has a mass of 2.32*10^30 kg. how long will it live if it converts all of its hydrogen into helium with an efficiency of 0.7%. 1 year = 365.25 days. lifetime= yearsWhat kind of object is the Messier Object M42, and where is it in the sky?
- The density and temperature in the solar corona are much higher than in the photosphere. (T/F)c) Derive the Schwarzschild criterion for the onset of convection in an ideal gas, namely d ln T d ln P 7-1 Y Explain all steps in your derivation, and justify any assumptions that you make. d) In a region of convective instability near the surface of a solar-type star of total mass M, the temperature and pressure are related approximately by the expression P KT5/2. Show that the temperature gradient for an ideal gas in hydrostatic = equilibrium in this convection zone is given by dT dr 2Gm(r)μ 5Rr² Further, assuming that the mass in the convection zone is small compared to M, show that at a depth h measured from the top of the convection zone, the temperature is approximately given by T = Ts + 2GMμ -h₂ 5RR² when his small compared to R, and Ts is the temperature at the top of the convection zone.