Question

In: Physics

Suppose a star the size of our Sun, but with mass 5.0 times as great, were...

Suppose a star the size of our Sun, but with mass 5.0 times as great, were rotating at a speed of 1.0 revolution every 18 days. If it were to undergo gravitational collapse to a neutron star of radius 14 km , losing three-quarters of its mass in the process, what would its rotation speed be? Assume also that the thrown- off mass carries off either

part a. no angular momentum

part b. its proportional share three-quarters of the initial angular momentum

Expert Solution

The mas of the star is

The radius of the star is

The moment of inertia of the star is

The period of revolution is

So, the angular speed of the star is

So, the initial angular momentum of the star is

PART A: When no momentum is lost

The radius of the collapsed star is

The mass of the collapsed star is

The moment of inertia of the collapsed star is

The angular momentum of the collapsed star is

The conservation of angular momentum gives us

So, the new rotational speed of the collapsed star is 39887 rad/s.

PART B: When three-quarters of the momentum is lost

The radius of the collapsed star is

The mass of the collapsed star is

The moment of inertia of the collapsed star is

The angular momentum of the collapsed star is

The three-quarter of the initial angular momentum is lost.

So, the conservation of angular momentum gives us

So, the new rotational speed of the collapsed star is 9972 rad/s.

genius_generous answered 2 months ago

Why does a star that has 8 times the mass of the Sun have a shorter...

Why does a star that has 8 times the mass of the Sun have a shorter lifetime on the Main Sequence than a star that has a mass of 2 times the mass of the Sun?

Write an essay about the expected life cycle of a star the mass of our Sun....

Write an essay about the expected life cycle of a star the mass of our Sun. Please include the following in your discussion • molecular cloud • protostar • main sequence • red giant branch • horizontal branch • asymptotic branch • planetary nebula • white dwarf

Suppose we discover a star which has twice the radius of the Sun and 4 times...

Suppose we discover a star which has twice the radius of the Sun and 4 times temperature of the Sun. What will be its luminosity in the units of solar luminosity? Calculate the distance to a star whose stellar parallax is 50 milli-arcseconds?

Suppose the Earth were a 0.10 Mʘ companion star to the Sun, but still orbiting with...

Suppose the Earth were a 0.10 Mʘ companion star to the Sun, but still orbiting with a semi-major axis of 1 AU about the real Sun. What would some alien astronomer measure the spectral line splitting width to be of the blue-green (λ=490 nm) line in the Hydrogen spectrum of the Sun? Express your answer in units of nm

A certain red giant star has a luminosity of 100,000 times that of the Sun and...

A certain red giant star has a luminosity of 100,000 times that of the Sun and is located 600 light-years from Earth. If the apparent magnitude of the star is observed to be m=0, calculate the rate of interstellar extinction in the direction of the star. If someone could show me step by step how to solve this I would be appreciative.

Consider a star has the same central conditions as our Sun: - assuming that the core...

Consider a star has the same central conditions as our Sun: - assuming that the core is comprised of hydrogen, what is the extent of ionisation in the core due to the temperature? - sometimes an approximation is made that the entire core of the star is entirely ionised, comment on the validity of this assumption.?

A neutron star has a mass of 3.35 × 1030 kg (about the mass of our...

A neutron star has a mass of 3.35 × 1030 kg (about the mass of our sun) and a radius of 6.09 × 103 m. Suppose an object falls from rest near the surface of such a star. How fast would it be moving after it had fallen a distance of 0.013 m? (Assume that the gravitational force is constant over the distance of the fall, and that the star is not rotating.)

Our sun will first become a red giant star when it leaves the Main Sequence, as...

Our sun will first become a red giant star when it leaves the Main Sequence, as it goes from core Hydrogen burning to shell Hydrogen burning. After it has exhausted all of the fusion reactions possible, perhaps some Helium fusion in there as well, it will leave a corpse called a White Dwarf, where there is a crystalline core of carbon and mixed ash products, surrounded by

The sun's mass is about 2.7 x 10^7 times greater than the moon's mass. The sun...

The sun's mass is about 2.7 x 10^7 times greater than the moon's mass. The sun is about 400 times farther from Earth than the moon. How does the gravitational force exerted on Earth by the sun compare with the gravitational force exerted on Earth by the moon? Use complete sentences.

If the Sun were to become a black hole but maintain all of its mass, what...

If the Sun were to become a black hole but maintain all of its mass, what would be its Schwarzschild radius? Given this and the fact that Earth’s average distance from the Sun is about 150 million km, would the gravity of the black hole pull Earth into it? Why or why not?