Concept explainers
When a star like our Sun exhausts its fuel, thermonuclear reactions in its core cease, and it collapses to become a white dwarf. Often the star will blow off its outer layers and lose some mass before it collapses. Suppose a star with the Sun’s mass and radius is rotating with period 25 days and then it collapses to a white dwarf with 60% of the Sun’s mass and a rotation period of 131 s. What’s the radius of the white dwarf? Compare your answer with the radii of Sun and Earth.
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
Essential University Physics (3rd Edition)
Additional Science Textbook Solutions
Essential University Physics: Volume 1 (3rd Edition)
The Cosmic Perspective Fundamentals (2nd Edition)
University Physics with Modern Physics (14th Edition)
University Physics (14th Edition)
The Cosmic Perspective (8th Edition)
College Physics (10th Edition)
- A neutron star is a cold, collapsed star with nuclear density. A particular neutron star has a mass twice that of our Sun with a radius of 12.0 km. (a) What would be the weight of a 100-kg astronaut on standing on its surface? (b) What does this tell us about landing on a neutron star?arrow_forwardA massive black hole is believed to exist at the center of our galaxy (and most other spiral galaxies). Since the 1990s, astronomers have been tracking the motions of several dozen stars in rapid motion around the center. Their motions give a clue to the size of this black hole. a. One of these stars is believed to be in an approximately circular orbit with a radius of about 1.50 103 AU and a period of approximately 30 yr. Use these numbers to determine the mass of the black hole around which this star is orbiting, b. What is the speed of this star, and how does it compare with the speed of the Earth in its orbit? How does it compare with the speed of light?arrow_forwardA black hole is an object so massive that not even light can escape, one way to define the size of a black hole is by the Schwarzschild Radius, which is the radius at which the escape velocity is equal to the speed of light. If we were to condense the Earth into a black hole, what would be the size of its Schwarzschild Radius?arrow_forward
- A typical neutron star may have a mass equal to that of the Sun (m =1.99x10 30 kg) but a radius of only 10 km. a) What is the gravitational acceleration at the surface of such a star? b) How fast would an object be moving if it fell from rest through a distance of 1.0 m on such a star?arrow_forwardAstronomers discover a binary system with a period of 90 days. Both stars have a mass twice that of the Sun. How far apart are the two stars? Both stars revolve around the center of mass in an orbit with radius r. F2oni d=ar Fron2 The distance between the stars is 2r.arrow_forwardA pulsar may form when a star of medium mass dies. On July 4, 1054 CE, Chinese astronomers witnessed the death of a star that led to the formation of the pulsar in the Crab Nebula. Contemporary astronomers have measured the angular speed of the nebula's pulsar as ? = 1.89 ✕ 102 rad/s and have found that the pulsar is slowing down such that ? = 2.39 ✕ 10−9 rad/s2. (a) Determine the period of the pulsar's rotation. s(b) Determine the number of seconds by which this period increases each second (dT/dt).arrow_forward
- After the Sun exhausts its nuclear fuel, its ultimate fate may be to collapse to a white dwarf state. In this state, it would have approximately the same mass as it has now, but its radius would be equal to the radius of the Earth. (a) Calculate the average density of the white dwarf. kg/m³ (b) Calculate the surface free-fall acceleration. m/s² (c) Calculate the gravitational potential energy associated with a 3.38-kg object at the surface of the white dwarf.arrow_forwardAfter the Sun exhausts its nuclear fuel, its ultimate fate may be to collapse to a white dwarf state. In this state, it would have approximately the same mass as it has now, but its radius would be equal to the radius of the Earth. (a) Calculate the average density of the white dwarf. kg/m3 (b) Calculate the surface free-fall acceleration. m/s2 (c) Calculate the gravitational potential energy associated with a 4.36-kg object at the surface of the white dwarf. Need Help? Read Itarrow_forwardA star orbits a black hole in a circular orbit at a distance of 3.9x1012 meters and a period of 4 years. What is the mass of the black hole? kgarrow_forward
- Plaskett's binary (also known as HD 47129) in the constellation Monoceros is a star system of two blue giant stars. The orbital speed of both stars has been found to be 250km/s and the period is 14.4days. Assuming that both stars are of equal mass, determine the mass of each star. (Optional problem. Hint: use your intuition about the orbits of these stars.)arrow_forwardThree identical stars, of mass M, are arranged along a straight line separated by a distance L. The two extreme stars revolve around the central star. a) What is the period of rotation of the stars that revolve around the central star?b) What is the mechanical energy E of the system?arrow_forwardA typical neutron star may have a mass equal to that of the Sun but a radius of only 19 km. (a) What is the gravitational acceleration at the surface of such a star? (Enter the magnitude.) 3670000000000x m/s? (b) How fast would an object be moving if it fell from rest through a distance of 1.1 m on such a star? (Assume the star does not rotate.) m/sarrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University