UWC iKamva : EWP 211 $1 2022 x Photometry_of_the_Pleiades.pdf x DE Spectral_Classification.pdf X + X C O File | C:/Users/User/Downloads/Spectral_Classification.pdf To 5. One can determine the surface temperature of each star (i.e. the temperature of each star's photosphere) using the full spectrum in the top graph of each panel and Wien's Law T = _ 2.9X 10' where T is temperature in Kelvin and Apeak is the wavelength in Angstroms where the blackbody curve peaks. Determine the surface temperature of each star using the top graph of each panel by following the procedure below: a) Trace the underlying blackbody continuum in the top graph of each panel. (This is what the spectrum would look like with no absorption lines-i.e. a perfect blackbody.) b) In the second column of Table 3 write down the wavelength (in Angstroms) where the blackbody continuum in each panel peaks. If the peak is not shown on the graph, then write down a rough estimate of where you think the curve might peak c) Use Wien's Law (formula above) to calculate the surface temperature of each panel's star. Record your answer in column 3 of Table 3. Table 3 Panel Peak Wavelength (Angstroms) Surface Temperature (K) 6. It was later realized that the strength of a star's absorption lines can be predicted if the star's surface temperature is known. This is because the heat of a star can excite electrons up to higher energy levels. For example, most hydrogen atoms in very hot stars are ionized (the electron leaves the atom completely,) and thus show very weak Balmer Series absorption lines. Cool stars keep most of their electrons in the 1" energy level. The medium temperature stars show the strongest Balmer lines because most of their electrons start in the 2" energy level. Therefore, it is more intuitive to classify stars based on their temperature rather than on their Balmer lines alone. Astronomers reordered the classification sequence such that the hottest stars came first, but they retained the letters originally assigned to each star based on their Balmer line strengths. a) Reorder the classification sequence by listing the panel numbers from hottest star to coolest star in the first column of Table 4. b) In the second column of Table 4, write down the letter you assigned each panel in Table 2. CONGRATULATIONS, YOU JUST OBTAINED THE (NON-ALPHABETICAL) STELLAR CLASSIFICATION SEQUENCE USED BY ASTRONOMERS