Question

Figure 2 shows observations of the spectrum of another star, like the Sun but more distant, as seen from the Earth over the course of a year. The wavelength range shown is the same tiny portion of the spectrum shown in the bottom panel of the earlier figure, and the same two prominent iron lines are seen. From laboratory measurements of such atoms, it is known that the wavelengths of these two lines are hemit - 633.53 for the shorter wavelength (bluer) line Demi-633.68 m for the longer wavelength (redder) line 1 Measure the observed wavelength, obs. of the bluer line in each of the eight panels in Figure 2 Record your answer to the nearest 0.01 nm. The first one is marked for you. t=0 months: - 1 months: t = 2 months 1 - 3 months: t = 4 months: t = 5 months: t = 6 months: t = 12 months 2. What is the emitted wavelength of the bluer line? Hint, you do not need to measure this. As you can see, at 3 months, the observed wavelength is equal to the emitted wavelength, so the Doppler velocity of the star as seen from Earth is zero. Use your measurements and the Doppler formula to answer the following: 3. What is the Doppler velocity of the star att - O months, in km/see? Att-6 months? Att = 12 months?

Answer 1

Ware length of bluer line is 633.53 nm. ③ for doppler velocity, v= c. (as-do) c = Contant velocity of slor solar radiation = 3x 10 km/s. As = emitted ware lengen. ho a observed warelayin. using this equation, doppler relocuty can be calculated. at, t= 3 months, As=do. . Thus, vzo. at t= 0, so = 0. V=C = 3x108 m/s. = 3x105 km/s But at t = 6 months. & 12 months data for to is not available. kindly see the spectrum & Cleulate on your own.