Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 24, Problem 18Q
To determine
The reason for some AGN to have broad spectral lines while some do not.
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The difference in absolute magnitude between two objects is related to their fluxes by the flux-magnitude relation:
FA / FB = 2.51(MB - MA)
A distant galaxy contains a supernova with an absolute magnitude of -19. If this supernova were placed next to our Sun (M = +4.8) and you observed both of them from the same distance, how much more flux would the supernova emit than the Sun?
Fsupernova / FSun = ?
A planetary nebula expanded in radius 0.3 arc seconds in 30 years. Doppler measurements show the nebula is expanding at a rate of 35 km/s. How far away is the nebula in parsecs?
First, determine what distance the nebular expanded in parsecs during the time mentioned. Δd = vpc/sTs
So we first need to convert the rate into pc/s and the time into seconds:
vpc/s = vkm/s (1 pc / 3.09 x 1013km)
vpc/s = ?
Ts = (Tyr)(365 days/yr)(24 hrs/day)(3600 s/hr)
Ts = ? s
Δd= vpc/sTs
Therefore, Δd = ? pc
1) There is a one earth mass planet orbiting an M5 star of 0.2 Mo and luminosity 1x10-2 Lo-
A) How close does the planet need to be to the star in order to receive the same amount of energy
as the Earth receives from the sun?
B) What is the orbital period of the planet at this distance?
C) What is the magnitude of the radial velocity perturbation of the star?
D) If the system is edge on to us, would we be likely to detect this planet using the radial
velocity method?
Chapter 24 Solutions
Universe: Stars And Galaxies
Ch. 24 - Prob. 1QCh. 24 - Prob. 2QCh. 24 - Prob. 3QCh. 24 - Prob. 4QCh. 24 - Prob. 5QCh. 24 - Prob. 6QCh. 24 - Prob. 7QCh. 24 - Prob. 8QCh. 24 - Prob. 9QCh. 24 - Prob. 10Q
Ch. 24 - Prob. 11QCh. 24 - Prob. 12QCh. 24 - Prob. 13QCh. 24 - Prob. 14QCh. 24 - Prob. 15QCh. 24 - Prob. 16QCh. 24 - Prob. 17QCh. 24 - Prob. 18QCh. 24 - Prob. 19QCh. 24 - Prob. 20QCh. 24 - Prob. 21QCh. 24 - Prob. 22QCh. 24 - Prob. 23QCh. 24 - Prob. 24QCh. 24 - Prob. 25QCh. 24 - Prob. 26QCh. 24 - Prob. 27QCh. 24 - Prob. 28QCh. 24 - Prob. 29QCh. 24 - Prob. 30QCh. 24 - Prob. 31QCh. 24 - Prob. 32Q
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- An astronomical image shows two objects that have the same apparent magnitude, i.e., the same brightness. However, spectroscopic follow up observations indicate that while one is a star that is within our galaxy, at a distance dgal away, and has the same luminosity as the Sun, the other is a quasar and has 100x the luminosity of the entire Milky Way galaxy. What is the distance to the quasar? (You may assume, for this rough calculation, that the Milky Way has 1011 stars and that they all have the luminosity as the Sun.) Give your response in Mpc. Value: dgal = 49 pcarrow_forwardThe star HD 93250 in the Carina Nebula is a bright O-type star. It has a reported apparent magnitude in the V band of mV = 7.41 and V band absolute magnitude of MV = −6.14. Using these values calculate the distance to HD 93250 in parsec. The distance to HD 93250 has been measured by other means as 2350 pc. Compare your calculated value of the distance with the measured value, and give a possible explanation for any difference. Calculate the value of the interstellar extinction in the V band AV that would account for the difference in the distances. The parameter E(B − V ) = AB − AV , where AB and AV are the extinctions in the B and V bands, is often used to characterize interstellar extinction. For the star HD 93250 the value E(B − V ) = 0.48 has been measured. Given the above value of E(B − V ) for HD 93250, calculate the extinction in the B band, and explain why the parameter E(B − V ) is often called the “reddening.” The B band apparent magnitude of HD 93250 is mB = 8.12. Calculate…arrow_forwardIn SN1987a the neutrino signal arrived about 3 hours before the optical signal. This suggests that it took 3 hours for the shockwave to propagate out through the star. If the blue supergiant progenitor to SN1987a had a radius of 10 ?⊙ R ⊙ , and assuming the shockwave was spherical and propagated from the center of the star, estimate the speed of the shockwave in km/s.arrow_forward
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