Where are the most massive stars to be found in the main sequence of a Hertzsprung-Russell diagram? The Sun's spectral curve peaks in the yellow-green region of the spectrum (i.e., this region is the most intense part of its spectrum). The spectrum of Rigel (the star in the knee of Orion) peaks in the short-wavelength end of the visible spectrum. Compared to the Sun, Rigel is d. hotter and bluer. The luminosity of a star is a unique measure of it . Atoms in a thin, hot gas (such as a neon advertising sign), emit lightat specific wavelengths or colors, the pattern depending on the element. Spectral lines are of particular importance in astronomy because a. each different element has a characteristic line spectrum. How much longer can the Sun continue to generate energy by nuclear reactions in its core? d. About 5 billion years How do astronomers measure the masses of stars? By observing the motion of two stars in a binary star system What is the dominant mechanism by which energy is transported through the inner regions of the Sun? b. by photons (radiative transport of energy) If the surface temperatures of white dwarf stars are up to 4 times that of the Sun, why then are white dwarfs intrinsically so faint? very small Compared to a star in the middle of the Hertzsprung-Russell diagram, a star in the upper right part of the diagram is larger . The granular appearance of the surface of the Sun is evidence of what phenomenon occurring in or on the Sun? Which of the following particles or types of radiation will provide the most direct information on the energy generation processes that are occurring at the present time in the solar core? c. A star in the lower left part of the Hertzsprung-Russell diagram, compared toa star in the middle of the diagram, is Smaller Two stars have the same luminosity. One star is spectral class B and the other is spectral class K. From this information, we know that the K-type star is larger than the B-type star. How can we characterize the rotation of the Sun?Differential rotation, with the equator rotating faster than the poles Two stars, P and Q, can be seen in the same region of our sky with the same apparent brightness, but star Q is twice as far away as star P. What is the ratio of the intrinsic brightnesses (luminosities) of these stars (star P-to-star Q)? c
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