Two stars (a and b) in a binary system have apparent V-band magnitudes of 8.0 and 8.4 mag, and B-V colour indices of 0.3 and -0.5 mag, respectively. (a) Which star is brightest in the V-band? (b) Which star is brightest in the B-band? (c) Which star would appeal bluer to the naked eye? (d) What is the ratio
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- If a star has a surface temperature of 20,000 K (2.00 × 104 K), at what wavelength will it radiate the most energy?We will take a moment to compare how brightly a white dwarf star shines compared to a red giant star. For the sake of this problem, lets assume a white dwarf has a temperature roughly twice as large as a red giant star. As for their stellar radii, the white dwarf has a radius about 1/10000th that of a red giant star. With this in mind, how does the luminosity of a red giant star compare to that of a white dwarf? (Put differently, find the ratio of their luminosities a.k.a. how many times more luminous is the red giant than the white dwarf? An answer of less than 1 means the white dwarf is more luminous, an answer of 1 means they have the same luminosity, and an answer greater than 1 means the red giant is more luUsing Wien's Law for two black body objects with a temperature of 1000 K (fire) and 290 K (background), at what central wavelengths are the two objects radiating?
- The white dwarf star Sirius B has a luminosity of 0.025 L⊙. If you were 1 AU from Sirius B, would that star appear brighter or fainter than the full Moon appears from Earth? If Sirius B were substituted for the Sun, what would Earth’s average temperature become? (Earth’s current average temperature is T = 287K)Question 2: apparent magnitude my 1 = 305.9, b = −44.9 and is d=4.5 kpc from the Sun. a.) The integrated light from the Milky Way globular cluster NGC 104 has an 4.03 mag and absolute magnitude My -9.52 mag. It is located at b.) = = Estimate the amount of extinction between the Sun and 47 Tucanae in magnitudes. What does this value of extinction mean for the amount of attenuation by dust between Earth and NGC 104?.1. Spectral signatures can be described using luminosity values in different spectral regions. UV Blue Green Red NIR Forest 28 29 36 27 56 Water 22 23 19 13 8 Corn 53 58 59 60 71 Pasture 40 39 42 32 62 Assuming these signatures are influenced by atmospheric effects: is it possible to separate the different categories based on the values in this table? Which band (s) are the most useful for distinguishing between the different classes in this table and why?
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