| 01. | The luminosity of the Sun is 3.86 x 1033 erg/sec. Calculate how long the Sun must shine in order to release an amount of energy equal to that produced by complete mass-to-energy conversion of (a) a carbon atom, (b) 1 kilogram, and (c) the Earth. |
| 02. | Assuming that the current rate of hydrogen burning in the Sun remains constant, what fraction of the Sun's mass will be converted into helium over the next 5 billion years? How will this affect the overall chemical composition of the Sun? (Assume the PP-I chain is the only reaction, which converts four hydrogen nuclei (protons) into one helium nucleus (alpha particle) and at the same time releases an energy of 26.2 MeV.) |
| 03. | (a) Estimate how many kilograms of hydrogen the Sun has consumed over the past 4.6 billion years, and estimate the amount of mass that the Sun has lost as a result. Assume that the Sun's luminosity has remained constant during that time. (b) In fact, the Sun's luminosity when it first formed was only about 70% of its present value. With this in mind, explain whether your answers to part (a) are an overestimate or an underestimate. |
| 04. | In a typical solar oscillation, the Sun's surface moves up or down at a maximum speed of 0.1 m/s. An astronomer sets out to measure this speed by detecting the Doppler shift of an absorption line of iron with wavelength 557.6099 nm. What is the maximum wavelength shift that she will observe? |
| 05. | Calculate the wavelengths at which the photosphere, chromosphere, and corona emit the most radiation. (Hint: Treat each part of the atmosphere as a perfect blackbody. Assume average temperature of 50,000 K and 1.5x106 K for the chromosphere and corona, respectively.) |