Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
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Textbook Question
Chapter 17, Problem 1E
What two factors determine how bright a star appears to be in the sky?
Expert Solution & Answer
To determine
Two factors that determines the brightness of the star.
Explanation of Solution
Introduction:
Luminosity and distance are the two factors that determines the brightness of the star.
Luminosity
Luminosity is the total radiative power radiated by stars into space. It is total amount of electromagnetic power emitted by galaxy, star or astronomical object. It gives direct indication of brightness of the stars. It is a logarithmic measure of brightness of the stars. Distance
Brightness of the stars depends upon the amount of starlight reaching to the earth. More the distance lesser will be the amount of starlight and hence lesser will be the brightness of the stars. So, the distance is also important factor to measure the brightness of the stars.
Conclusion:
Luminosity and distance are the two factors that determines the brightness of the star.
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Chapter 17 Solutions
Astronomy
Ch. 17 - What two factors determine how bright a star...Ch. 17 - Explain why color is a measure of a star’s...Ch. 17 - What is the main reason that the spectra of all...Ch. 17 - What elements are stars mostly made of? How do we...Ch. 17 - What did Annie Cannon contribute to the...Ch. 17 - Name five characteristics of a star that can be...Ch. 17 - How do objects of spectral types L, T, and Y...Ch. 17 - Do stars that look brighter in the sky have larger...Ch. 17 - The star Antares has an apparent magnitude of 1.0,...Ch. 17 - Based on their colors, which of the following...
Ch. 17 - Order the seven basic spectral types from hottest...Ch. 17 - What is the defining difference between a brown...Ch. 17 - If the star Sirius emits 23 times more energy than...Ch. 17 - How would two stars of equal luminosity-one blue...Ch. 17 - Table 17.2 lists the temperature ranges that...Ch. 17 - Suppose you are given the task of measuring the...Ch. 17 - Star X has lines of ionized helium in its...Ch. 17 - The spectrum of the Sun has hundreds of strong...Ch. 17 - What are the approximate spectral classes of stars...Ch. 17 - Look at the chemical elements in Appendix K. Can...Ch. 17 - Appendix I lists some of the nearest stars. Are...Ch. 17 - Appendix J lists the stars that appear brightest...Ch. 17 - What star appears the brightest in the sky (other...Ch. 17 - Suppose hominids one million years ago had left...Ch. 17 - Why can only a lower limit to the rate of stellar...Ch. 17 - Why do you think astronomers have suggested three...Ch. 17 - Sam, a college student, just bought a new car....Ch. 17 - Would a red star have a smaller or larger...Ch. 17 - Two stars have proper motions of one arcsecond per...Ch. 17 - Suppose there are three stars in space, each...Ch. 17 - What would you say to a friend who made this...Ch. 17 - In Appendix J, how much more luminous is the most...Ch. 17 - Verify that if two stars have a difference of five...Ch. 17 - As seen from Earth, the Sun has an apparent...Ch. 17 - An astronomer is investigating a faint star that...Ch. 17 - The center of a faint but active galaxy has...Ch. 17 - You have enough information from this chapter to...Ch. 17 - Do the previous problem again, this time using the...Ch. 17 - Star A and Star B have different apparent...Ch. 17 - Star A and Star B have different apparent...Ch. 17 - The star Sirius A has an apparent magnitude of 1.5...Ch. 17 - Our Sun, a type G star, has a surface temperature...
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