EP WEBASSIGN FOR SEEDS/BACKMAN'S FOUNDA
14th Edition
ISBN: 9780357113325
Author: Seeds
Publisher: CENGAGE CO
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Chapter 14, Problem 8P
To determine
The peak wavelength associated with luminosity of Neutron star given in problem 7 and identifies the band of EM spectrum which it belongs.
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As we have discussed, Sirius B in the Sirius binary system is a white dwarf with MB ∼ 1M , LB ∼ 0.024L ,and rB ∼ 0.0084r . For such a white dwarf, the temperature at the center is estimated to be ∼ 107 K.If Sirius B’s luminosity were due to hydrogen fusion, what is the upper limit of the mass fraction of thehydrogen in such a white dwarf?Step 1: Calculate the observed energy production rate per unit mass (remember luminosity is energy outputper unit time).Step 2: Use the per unit mass energy generation rate of hydrogen fusion (via PP chain) to estimate thepossible hydrogen mass fraction given the condition at the center of the white dwarf.
As a star runs out of hydrogen to fuel nuclear fusion in its core, changes within the star usually cause it to leave the main sequence, expanding and cooling as it does so. Would a star with a radius 6 times that of the Sun, but a surface temperature 0.4 times that of the Sun, be more, or less luminous than the Sun?
Show and explain your reasoning.
You may assume the surface area of a sphere is A = 4πr2.
The center star in the head of the asterism Scorpius is Dschubba. Assume that Dschubba is a spherical blackbody with a surface temperature of 28,000 K and a radius of 5.16 × 109m, located at a distance of 123 parsecs from Earth. Determine the following for Dschubba:(a) luminosity relative to the Sun (note that L = 3.83 × 1026W ).(b) absolute bolometric magnitude (note that M = 4.74).(c) apparent bolometric magnitude.(d) radiant flux at the star’s surface (in SI unit).(e) radiant flux at Earth’s surface (in SI unit).(f) peak wavelength λmax when plotting the plank function against wavelength (in nm)
Chapter 14 Solutions
EP WEBASSIGN FOR SEEDS/BACKMAN'S FOUNDA
Ch. 14 - Prob. 1RQCh. 14 - Prob. 2RQCh. 14 - Prob. 3RQCh. 14 - Prob. 4RQCh. 14 - Prob. 5RQCh. 14 - Prob. 6RQCh. 14 - Prob. 7RQCh. 14 - Prob. 8RQCh. 14 - Prob. 9RQCh. 14 - Prob. 10RQ
Ch. 14 - Prob. 11RQCh. 14 - Prob. 12RQCh. 14 - Prob. 13RQCh. 14 - Prob. 14RQCh. 14 - Prob. 15RQCh. 14 - Prob. 16RQCh. 14 - If the Sun has a Schwarzschild radius, why isnt it...Ch. 14 - Prob. 18RQCh. 14 - Prob. 19RQCh. 14 - Prob. 20RQCh. 14 - Prob. 21RQCh. 14 - In what sense is a black hole actually black?Ch. 14 - If you are falling into a black hole and you point...Ch. 14 - Prob. 24RQCh. 14 - Prob. 25RQCh. 14 - Prob. 26RQCh. 14 - How Do We Know? How does peer review make fraud...Ch. 14 - Prob. 1PCh. 14 - Prob. 2PCh. 14 - Prob. 3PCh. 14 - Prob. 4PCh. 14 - Prob. 5PCh. 14 - Prob. 6PCh. 14 - Prob. 7PCh. 14 - Prob. 8PCh. 14 - Prob. 9PCh. 14 - Prob. 10PCh. 14 - Prob. 11PCh. 14 - Prob. 12PCh. 14 - Prob. 13PCh. 14 - Prob. 14PCh. 14 - Prob. 15PCh. 14 - Prob. 16PCh. 14 - Prob. 1SOPCh. 14 - Prob. 2SOPCh. 14 - Prob. 1LTLCh. 14 - Prob. 2LTLCh. 14 - Prob. 3LTLCh. 14 - Prob. 4LTLCh. 14 - Prob. 5LTL
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- Consider the image above of the Cassiopeia A (Cas A) supernova remnant. The supernova explosion that caused this remnant was observed on earth about 300 years ago. It is about 3000 pc away. Since that time, the shockwave from the supernova has expanded to form the roughly spherical cloud pictured above. From the center point to the edge of the cloud is about 3 pc. Compute the angular diameter of the Cas A supernova remnant as viewed from Earth. Express your answer in arcminutes.arrow_forwardFor the PP chain 0.7% of the mass participating in nuclear fusion is liberated as energy which produces a star's luminosity. Assume that the core of a main sequence star consists of 10% of its total mass. Hence, estimate the lifetime of a star on the main sequence in terms of its luminosity L/L. Give your answer in years. You may use the observed mass-luminosity relation L x M³.5, where M is the star's total mass. Using typical values, calculate estimates for the main sequence lifetime of a KO star and a 05 star. Describe briefly why your estimate might be more accurate for K stars compared to O stars.arrow_forwardA cloud of mean number density n ~ 3000 cm-3 and radius 3 pc has an ionising source with luminosity at 13.6 eV of L13.6eV = 2.18 x 109 erg s- at the centre. (a) What is the size of the HII region in pe? [og = 2 x 10-13 cms-]. %3D (b) What assumptions are involved in part a) (c) Discuss why the HII region will drive a shock into the rest of the cloud, and calculate the post-shock density. (d) Show why this HII region will destroy the cloud.arrow_forward
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