Foundations of Astronomy (MindTap Course List)
14th Edition
ISBN: 9781337399920
Author: Michael A. Seeds, Dana Backman
Publisher: Cengage Learning
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Chapter 9, Problem 21RQ
To determine
The observations that should make to classify a star according to its luminosity and the reason to choose the method.
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The Hα spectral line has a rest wavelength of 6562.8 ˚A (remember: 1 ˚A = 10−10 m). In star A, the lineis seen at 6568.4 ˚A, in star B it’s seen at 6560.3 ˚A, and in star C it’s seen at 6562.8 ˚A. Which star ismoving the fastest (along the line of sight) and what is the radial velocity of each star?
The origin of the above quote (with "flame" or "candle" sometimes substituted for "light") is unclear. It is often attributed to either Lao Tzu or to the character Eldon Tyrell from the 1982 movie Blade Runner.
Stars follow a similar law, although the factor isn't precisely 1/2. In this problem, you will figure out the precise factor that the quote should have to apply to stars.
Using the proportionality relationships for stellar luminosity as a function of mass and stellar lifetime as a function of mass, combine the two equations to arrive at a proportionality for stellar lifetime as a function of luminosity.
Consider a star with luminosity twice that of the Sun's. Compute the star's main sequence lifetime as a multiple of the Sun's main sequence lifetime. Enter your result below as a decimal. For example, if you found TT⊙=0.3, enter "0.3". (Here T is the star's lifetime and T⊙ is the Sun's main sequence lifetime.
Using solar units, we find that a star has 4 times the luminosity of the Sun, a mass 1.25 times the mass of the Sun, and a surface temperature of 4090 K (take the Sun's surface temperature to be 5784 K for the sake of this problem). This means the star has a radius of.................... solar radii and is a .................... star (use the classification).
Chapter 9 Solutions
Foundations of Astronomy (MindTap Course List)
Ch. 9 - Prob. 1RQCh. 9 - Why was the Hipparcos satellite able to make more...Ch. 9 - Prob. 3RQCh. 9 - Prob. 4RQCh. 9 - Prob. 5RQCh. 9 - Prob. 6RQCh. 9 - Prob. 7RQCh. 9 - Prob. 8RQCh. 9 - Prob. 9RQCh. 9 - Prob. 10RQ
Ch. 9 - Prob. 11RQCh. 9 - Prob. 12RQCh. 9 - Prob. 13RQCh. 9 - Prob. 14RQCh. 9 - Prob. 15RQCh. 9 - Prob. 16RQCh. 9 - Prob. 17RQCh. 9 - Prob. 18RQCh. 9 - Prob. 19RQCh. 9 - Prob. 20RQCh. 9 - Prob. 21RQCh. 9 - Prob. 22RQCh. 9 - Prob. 23RQCh. 9 - Prob. 24RQCh. 9 - Prob. 25RQCh. 9 - Prob. 26RQCh. 9 - Prob. 27RQCh. 9 - Prob. 28RQCh. 9 - Prob. 29RQCh. 9 - Prob. 30RQCh. 9 - Prob. 31RQCh. 9 - Prob. 32RQCh. 9 - How Do We Know? In what way are basic scientific...Ch. 9 - Prob. 1PCh. 9 - Prob. 2PCh. 9 - Prob. 3PCh. 9 - Prob. 4PCh. 9 - Complete the following table:Ch. 9 - Prob. 6PCh. 9 - Prob. 7PCh. 9 - Prob. 8PCh. 9 - Prob. 9PCh. 9 - Prob. 10PCh. 9 - Prob. 11PCh. 9 - Prob. 12PCh. 9 - Prob. 13PCh. 9 - Prob. 14PCh. 9 - Prob. 15PCh. 9 - Prob. 16PCh. 9 - Prob. 17PCh. 9 - Prob. 18PCh. 9 - Prob. 19PCh. 9 - Prob. 20PCh. 9 - Prob. 1SOPCh. 9 - Prob. 2SOPCh. 9 - Prob. 3SOPCh. 9 - Look at the image on the opening page of this...Ch. 9 - Prob. 2LTLCh. 9 - Prob. 3LTLCh. 9 - Prob. 4LTL
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- = A star population is composed of stars with masses in the range between 1M and 150M. The initial mass function is = 0 (M/M)-2.3, where o (Mo). The luminosity of a star = (M/M) 3.3. Calculate the percentage of the total luminosity of the stars in the population which is produced by stars with mass between 120M and 150M. scales with its mass as L/Larrow_forwardOne way to calculate the radius of a star is to use its luminosity and temperature and assume that the star radiates approximately like a blackbody. Astronomers have measured the characteristics of central stars of planetary nebulae and have found that a typical central star is 16 times as luminous and 20 times as hot (about 110,000 K) as the Sun. Find the radius in terms of the Sun’s. How does this radius compare with that of a typical white dwarf?arrow_forwardAn O8 V star has an apparent visual magnitude of +5. Use the method of spectroscopic parallax to estimate the distance to the star (in pc). (Hints: Refer to one of the H–R diagrams in the chapter, and use the magnitude–distance formula, d = 10(mV − MV + 5)/5 where d is the distance in parsecs, mV and MV are the apparent and absolute visual magnitude respectively.)arrow_forward
- A star has a measured radial velocity of 300 km/s. If you measure the wavelength of a particular spectral line of Hydrogen as 657.18 nm, what was the laboratory wavelength (in nm) of the line? (Round your answer to at least one decimal place.) nm Which spectral line does this likely correspond to? Balmer-alpha (656.3 nm) Balmer-beta (486.1 nm) Balmer-gamma (434.0 nm) Balmer-del ta (410.2 nm)arrow_forwardWe 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 luarrow_forwardQuestion 32 Consider three Main Sequence stars, an O tar, an F star and a K star, each with an apparent magnitude of 2. Which star is the most luminous? They're all the same luminosity. The O star The F star The K star Question 33 Consider three Main Sequence stars, an O star, an F star and a K star, each with an apparent magnitude of 2. Which star appears the brightest in the night sky? The O star The F star O The K star O They all appear the same. Please answer botharrow_forward
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