Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 25, Problem 18E
Assume that the Sun orbits the center of the Galaxy at a speed of 220 km/s and a distance of 26,000 lightyears from the center.
A. Calculate the circumference of the Sun’s orbit, assuming it to be approximately circular. (Remember that the circumference of a circle is given by 2pR, where R is the radius of the circle. Be sure to use consistent units. The conversion from light-years to km/s can be found in an online calculator or appendix, or you can calculate it for yourself: the
B. Calculate the Sun’s period, the “galactic year.” Again, be careful with the units. Does it agree with the number we gave above?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
given:
a (distance to center of galaxy in AU) = 1,717,914,439 AU
P (suns orbital period in years) = 203,782,828.3 years
M (mass of milky way galaxy in solar masses) = 1.22 x 10^11 Msun
Question:
Assume the Milky Way Galaxy is made up entirely of stars like the Sun, i.e. on average each star has the mass of 1 MSun. Under this assumption, approximately how many stars are there in our galaxy? Express this answer in billions of stars (1 billion = 109).
A galaxy with a spherically symmetric distribution of matter has a mass density profile of the type p(r) ∞ 1/r, where r is the radial coordinate from the centre
of the galaxy. To what type of circular velocity (r) does this correspond?
Select one:
a. (r)
O b.
c.
O d.
(r) ~ r
(r) ~ √r
(r): = constant
The Tully-Fischer method relies on being able to relate the mass of a galaxy to its rotation velocity. Stars in the outer-most regions of the Milky Way galaxy, located at a distance of 50 kpc from the galactic centre, are observed to orbit at a speed vrot = 250 km s−1. Using Kepler’s 3rd Law, determine the mass in the Milky Way that lies interior to 50 kpc. Express your answer in units of the Solar mass.
Chapter 25 Solutions
Astronomy
Ch. 25 - Explain why we see the Milky Way as a faint band...Ch. 25 - Explain where in a spiral galaxy you would expect...Ch. 25 - Describe several characteristics that distinguish...Ch. 25 - Briefly describe the main parts of our Galaxy.Ch. 25 - Describe the evidence indicating that a black hole...Ch. 25 - Explain why the abundances of heavy elements in...Ch. 25 - What will be the long-term future of our Galaxy?Ch. 25 - Suppose the Milky Way was a band of light...Ch. 25 - Suppose somebody proposed that rather than...Ch. 25 - The globular clusters revolve around the Galaxy in...
Ch. 25 - Shapley used the positions of globular clusters to...Ch. 25 - Consider the following five kinds of objects: open...Ch. 25 - The dwarf galaxy in Sagittarius is the one closest...Ch. 25 - Suppose three stars lie in the disk of the Galaxy...Ch. 25 - Why does star formation occur primarily in the...Ch. 25 - Where in the Galaxy would you expect to find Type...Ch. 25 - Suppose that stars evolved without losing...Ch. 25 - Assume that the Sun orbits the center of the...Ch. 25 - The Sun orbits the center of the Galaxy in 225...Ch. 25 - Suppose the Sun orbited a little farther out, but...Ch. 25 - We have said that the Galaxy rotates...Ch. 25 - If our solar system is 4.6 billion years old, how...Ch. 25 - Suppose the average mass of a star in the Galaxy...Ch. 25 - The first clue that the Galaxy contains a lot of...Ch. 25 - The best evidence for a black hole at the center...Ch. 25 - The next step in deciding whether the object in...Ch. 25 - Suppose the Sagittarius dwarf galaxy merges...
Additional Science Textbook Solutions
Find more solutions based on key concepts
10. Figure Q15.10 Q shows a history graph and a snapshot graph for a wave pulse on a string. They describe the ...
College Physics: A Strategic Approach (4th Edition)
3. Which would you expect to have a higher melting point: sodium chloride, NaCl, or aluminum oxide, Al2O3?
(a) ...
Conceptual Physical Science (6th Edition)
Multiple Choice Questions When you shine a very narrow beam of white light on a grating in a dark room, what do...
College Physics
Choose the best answer to etch of the following. Explain your reasoning. Scientists estimate the central temper...
The Cosmic Perspective Fundamentals (2nd Edition)
63. Tuning a cello. A cellist tunes the C-string of her instrument to a fundamental frequency of 65.4 Hz. The v...
College Physics (10th Edition)
A glass beaker measures 14 cm high by 5.0 cm in diameter. Empty, it floats in water with one-third of its heigh...
Essential University Physics: Volume 1 (3rd Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- 1. A distant galaxy has an apparent magnitude of 10 and is 4,000 kpc away. What is its absolute magnitude? (Round your answer to at least one decimal place.) The difference in absolute magnitude between two objects viewed from the same distance is related to their fluxes by the flux-magnitude relation. FA/FB= 2.51(MB − MA) 2. How does the absolute magnitude of this galaxy compare to the Milky Way (M = −21)?arrow_forwardAn astronomer observed the motions of some galaxies. Based on his observations, he made the following statements. Which one of them is most likely to be false? Take Hubble's constant to be 67 km/s/Mpc. A. A galaxy observed to be moving away from us at a speed of 70 km/s is at a distance of about 1 Mpc from us. B. A galaxy observed to be moving away from us at a speed of 700 km/s is at a distance of about 10 Mpc from us. C. A galaxy observed to be moving away from us at a speed of 7000 km/s is at a distance of about 100 Mpc from us. D. A galaxy observed to be moving away from us at a speed of 70000 km/s is at a distance of about 1 Gpc from us. Is the answer D? Thank you!arrow_forwardEstimating the mass of the Milky Way a) Assuming the Sun moves in a circular orbit of radius 8 kiloparsecs around the center of the Milky Way, and that its orbital speed is 220 km/s, calculate how many years it takes the Sun to complete one orbit of the Galaxy. Remember to convert kiloparsecs to kilometers. b) Using the modified form of Kepler's third law (introduced in Lecture 13, for measuring the combined masses of binary stars), R³ m+ M = estimate the mass of the Milky Way enclosed within 8 kpc (Sun's orbit radius). The mass of the Milky Way inside p² I the Sun's orbit can be represented as a single mass (M) located at its center, and the mass of the Sun (m) can be considered infinitesimally small compared to the Milky Way's (i.e., m < M). c) Is this estimate of the Milky Way's mass an upper or lower limit? Explain your reasoning.arrow_forward
- For a circular velocity profile of the type (r) = ar¹ ar1/9, where a is a constant and r is the radial distance from the centre of a spiral galaxy, find the ratio (r)/(r), where (r) is the epicyclic frequency and 2(r) is the angular velocity. Enter your answer to 2 decimal places.arrow_forwardApproximate values of length (in meters) 107 Diameter of Earth 1011 Distance from Earth to Sun 1016 Distance traveled by light in one year 1021 Diameter of the Milky Way Galaxy 1022 Distance from Earth to the nearest galaxy 1025 Distance from Earth to the edge of the known universearrow_forwardUsing MBH = 6.6 × 10 Mo, calculate the below. a. Find radius of the Schwarzschild sphere (Schwarzschild radius Rs). You can calculated from the appropriate formula or just use the fact that for an object of 1 solar mass Rs = 3 km. b. Express Rs in km, in AU, in parsecs. c. Using the distance to M87 and your result above, find angular radius of the SMBH (Schwarzschild radius). Express it in arcseconds (") and micro- arcseconds (pas) d. Take the radius of Pluto's orbit equal to 40 AU and find its angular size (in micro-arcseconds, pas) at the distance of M87.arrow_forward
- The difference in absolute magnitude between two objects at the same distance is related to their fluxes by the flux-magnitude relation. FA FB = 2.51(MB − MA) A distant galaxy contains a type I classical Cepheid whose period results in an absolute magnitude estimate of −6.3. If this star were placed next to our Sun (M = +4.8) and you observed them both from the same distance, how much more flux would the Cepheid emit than the Sun? FCepheid FSun = If a galaxy contains a supernova that at its brightest has an apparent magnitude of +11, how far away is the galaxy? Assume that the absolute magnitude of the supernova is −18. Hint: Use the magnitude-distance formula: d = 10(mV − MV + 5)/5 . The hydrogen Balmer line H? has a wavelength of 486.1 nm. It is shifted to 559.7 nm in a quasar's spectrum. What is the redshift of this quasar? (Hint: What is Δ??)arrow_forwardHow astronomers determine the distance of a galaxy? Explain.arrow_forwarda) Calculate the period of the solar system's orbit around the Milky Way. Assume that we are 8.5 kpc from the galactic center and assume that the mass of the Milky Way interior to our orbit is ~ 10¹¹ solar masses. Alpha Centauri is a multiple star system only 1.34 parsecs away. The apparent magnitudes of the two main stars are: a Cen A: my = +0.01; a Cen B: my = +1.33. b) Calculate the ratio of the flux we receive in the V filter from a Cen A to the flux we receive from a Cen B. c) Calculate the absolute magnitude My of a Cen B.arrow_forward
- 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_forwardSuppose we find an Earth-like planet around one of our nearest stellar neighbors, Alpha Centauri (located only 4.4 light-years away). If we launched a "generation ship" at a constant speed of 1500.00 km/s from Earth with a group of people whose descendants will explore and colonize this planet, how many years before the generation ship reached Alpha Centauri? (Note there are 9.46 ××1012 km in a light-year and 31.6 million seconds in a year.arrow_forwardGalaxy B moves away from galaxy A at 0.541 times the speed of light. Galaxy C moves away from galaxy B in the same direction at 0.701 times the speed of light. How fast does galaxy C recede from galaxy A? Express your answer as a fraction of the speed of light. Galaxy C recedes from Galaxy A atarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStax
Foundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning