Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
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Textbook Question
Chapter 23, Problem 52E
What was the average density of the star that became SN 1987A? How does it compare to the average density of Earth? The mass was 20 times that of the Sun and the radius was 41 times that of the Sun.
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Chapter 23 Solutions
Astronomy
Ch. 23 - How does a white dwarf differ from a neutron star?...Ch. 23 - Describe the evolution of a star with a mass like...Ch. 23 - Describe the evolution of a massive star (say, 20...Ch. 23 - How do the two types of supernovae discussed in...Ch. 23 - A star begins its life with a mass of 5 MSunbut...Ch. 23 - If the formation of a neutron star leads to a...Ch. 23 - How can the Crab Nebula shine with the energy of...Ch. 23 - How is a nova different from a type Ia supernova?...Ch. 23 - Apart from the masses, how are binary systems with...Ch. 23 - What observations from SN 1987A helped confirm...
Ch. 23 - Describe the evolution of a white dwarf over time,...Ch. 23 - Describe the evolution of a pulsar over time, in...Ch. 23 - How would a white dwarf that formed from a star...Ch. 23 - What do astronomers think are the causes of...Ch. 23 - How did astronomers finally solve the mystery of...Ch. 23 - Arrange the following stars in order of their...Ch. 23 - Would you expect to find any white dwarfs in the...Ch. 23 - Suppose no stars more massive than about 2 MSunhad...Ch. 23 - Would you be more likely to observe a type II...Ch. 23 - Astronomers believe there are something like 100...Ch. 23 - Would you expect to observe every supernova in our...Ch. 23 - The Large Magellanic Cloud has about one-tenth the...Ch. 23 - Look at the list of the nearest stars in Appendix...Ch. 23 - If most stars become white dwarfs at the ends of...Ch. 23 - If a 3 and 8 MSunstar formed together in a binary...Ch. 23 - You have discovered two star clusters. The first...Ch. 23 - A supernova remnant was recently discovered and...Ch. 23 - Based upon the evolution of stars, place the...Ch. 23 - What observations or types of telescopes would you...Ch. 23 - How would the spectra of a type II supernova be...Ch. 23 - The ring around SN 1987A (Figure 23.12) initially...Ch. 23 - What is the acceleration of gravity (g) at the...Ch. 23 - What is the escape velocity from the Sun? How much...Ch. 23 - What is the average density of the Sun? How does...Ch. 23 - Say that a particular white dwarf has the mass of...Ch. 23 - What is the escape velocity from the white dwarf...Ch. 23 - What is the average density of the white dwarf in...Ch. 23 - Now take a neutron star that has twice the mass of...Ch. 23 - What is the escape velocity from the neutron star...Ch. 23 - What is the average density of the neutron star in...Ch. 23 - One way to calculate the radius of a star is to...Ch. 23 - According to a model described in the text, a...Ch. 23 - Do the same calculations as in Exercise 23.42 but...Ch. 23 - If the Sun were replaced by a white dwarf with a...Ch. 23 - A supernova can eject material at a velocity of...Ch. 23 - A supernova remnant was observed in 2007 to be...Ch. 23 - The ring around SN 1987A (Figure 23.12) started...Ch. 23 - Before the star that became SN 1987A exploded, it...Ch. 23 - What is the radius of the progenitor star that...Ch. 23 - What is the acceleration of gravity at the surface...Ch. 23 - What was the escape velocity from the surface of...Ch. 23 - What was the average density of the star that...Ch. 23 - If the pulsar shown in Figure 23.16 is rotating...
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- What is the acceleration of gravity at the surface of the star that became SN 1987A? How does this g compare to that at the surface of Earth? The mass was 20 times that of the Sun and the radius was 41 times that of the Sun.arrow_forwardWhat was the escape velocity from the surface of the SN 1987A progenitor star? How much greater is it than the escape velocity from Earth? The mass was 20 times that of the Sun and the radius was 41 times that of the Sun.arrow_forwardWhat is the radius of the progenitor star that became SN 1987A? Its luminosity was 100,000 times that of the Sun, and it had a surface temperature of 16,000 K.arrow_forward
- Before the star that became SN 1987A exploded, it evolved from a red supergiant to a blue supergiant while remaining at the same luminosity. As a red supergiant, its surface temperature would have been approximately 4000 K, while as a blue supergiant, its surface temperature was 16,000 K. How much did the radius change as it evolved from a red to a blue supergiant?arrow_forwardA star has a period of P = 37 days. It has a radius of 5.7 times the radius of the sun. Calculate it's equatorial speed Vrot. Answer: Okm/s Om/s Check A star has a radius of 5.7 times the radius of the sun and a mass of 18 times the mass of the sun. It rotates at 0.7 of the critical speed W, the speed at which it's surface at the equator is actually in orbit. Recall Vrot is calculated at the equator and W= Vrot/Vorb Calculate it's period P. Answer: Odays Ohours Oseconds Checkarrow_forwardA star with spectral type A0 has a surface temperature of 9600 K and a radius of 2.2 RSun. How many times more luminous is this star than the Sun? (if it is less luminous enter a number less than one) This star has a mass of 3.3 MSun. Using the simple approximation that we made in class, what is the main sequence lifetime of this star? You may assume that the lifetime of the sun is 1010 yr. Compare this to the lifetime of a A0 star listed in Table 22.1 (computed using a more sophisticated approach). Is the value you calculated in the previous problem longer or shorter than what is reported in the table? (L for longer, S for shorter) (You only get one try at this problem.)arrow_forward
- 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).arrow_forwardA 46M Sun main sequence star loses 1 Msun of mass over 105 years. (Due to the nature of this problem, do not use rounded intermediate values in your calculations including answers submitted in WebAssign.) How many solar masses did it lose in a year? By how much will its luminosity decrease if this mass loss continues over 0.8 million years? Due to the nature of this problem, for all parts, do not use rounded intermediate values in your calculations-including answers submitted in WebAssign. To determine the number of solar masses lost per year, divide the mass lost by the number of years over which it was lost. Mlost tlost-yr Part 1 of 3 dM = dM = MSun/yrarrow_forwardA red giant star might have radius = 104 times the solar radius, and luminosity = 1730 times solar luminosity. Use the data given below to calculate the temperature at the surface of the red giant star. Data: solar radius R = 7 x 108 meters solar luminosity L = 4 x 1026 watts Stefan-Boltzmann constant a = 5.67 x 10-8 W m² K-4 (in K) A: 1226 OB: 1434 OC: 1678 OD: 1963 OE: 2297 OF: 2688 OG: 3145 OH: 3679arrow_forward
- Why are Cepheid variables important? O Cepheids variables are pulsating stars whose pulsation periods are directly related to their true luminosities. Therefore they can be used as distance indicators. O Cepheids variables are supermassive stars that are on the verge of becoming supernovae. Therefore they allow us to choose candidates to watch if we hope to observe a supernova. O Cepheid variables are stars that vary in brightness because they harbor a black hole. Therefore, they provide direct evidence for black holes. O Cepheids variables are a type of irregular galaxy, much more common in the early universe. Therefore they help to understand how galaxies formed.arrow_forwardWhat is the free-fall time of a 10 MSun main-sequence star? O 100 hours O 10 hours O 1 hour O 0.1 hoursarrow_forwardThis star has a mass of 3.3 MSun. What is the main sequence lifetime of this star? You may assume that the lifetime of the sun is 1010 yr. Hint: The simple relation is that lifetime is proportional to mass divided by luminosity. If you use these quantities in solar masses and solar luminosities, then this relation tells you how many times longer than the Sun the star will live.arrow_forward
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