Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 7: Problem 32

What is an accretion disk?

Short Answer

Expert verified
An accretion disk is a rotating disk of material around a central body, formed by matter spiraling inward due to gravity.

Step by step solution

01

Define Accretion Disk

An accretion disk is a structure formed by diffuse material in orbital motion around a central body, such as a star or a black hole. The material in the disk is drawn toward the central body due to gravitational attraction.
02

Explain the Formation

The accretion disk forms when matter, such as gas and dust, spirals in toward the central body. The material loses angular momentum due to friction and other forces, allowing it to move inward and form a disk.
03

Describe the Physical Properties

The material in an accretion disk becomes hot and emits electromagnetic radiation, often visible as light. The inner regions of the disk are usually hotter and more luminous than the outer regions.
04

Relate to Astrophysical Context

Accretion disks are commonly found around young stars, black holes, white dwarfs in binary systems, and active galactic nuclei. They are important for understanding processes such as star formation and energy output from black holes.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Gravitational Attraction
Gravitational attraction is the force that pulls objects toward one another. This force is responsible for the structure and behavior of accretion disks.
In an accretion disk, material such as gas and dust is drawn toward a central body due to this gravitational pull.
The central body can be a star, a black hole, or another massive celestial object.
Over time, the gravitational force causes the material to spiral inward, gradually forming a disk around the central body.
This process is fundamental to the accretion disk's formation and dynamics.
Angular Momentum
Angular momentum describes the rotational motion of objects and is conserved in isolated systems.
In the context of accretion disks, the material has angular momentum as it orbits the central body.
As the material spirals inward, it loses angular momentum due to friction and other interactions.
This loss of angular momentum allows the material to move closer to the central body and contributes to the formation of the disk.
The conservation and transfer of angular momentum are key to understanding how accretion disks evolve over time.
Electromagnetic Radiation
Electromagnetic radiation is the energy emitted by charged particles and can be seen in various forms such as light, radio waves, and X-rays.
In an accretion disk, the material becomes very hot as it spirals inward, causing it to emit electromagnetic radiation.
This radiation can be observed with telescopes and provides important information about the properties and behavior of the accretion disk.
The inner regions of the disk are usually hotter and emit more radiation than the outer regions.
The study of this radiation helps scientists understand the conditions and processes occurring within the disk.
Astrophysics
Astrophysics is the branch of astronomy that deals with the physical properties and interactions of celestial objects.
Accretion disks are significant in astrophysics because they are common around various celestial bodies such as young stars, black holes, and white dwarfs in binary systems.
They play a crucial role in processes like star formation, where young stars gather material from their surrounding disks.
In black holes, accretion disks contribute to the high energy and radiation output observed.
Understanding accretion disks helps astrophysicists learn more about the life cycles of stars and the energetic phenomena in the universe.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The best current technology can measure radial velocities of about \(1 \mathrm{m} / \mathrm{s}\). Suppose you are observing a spectral line with a wavelength of 575 nanometers (nm). How large a shift in wavelength would a radial velocity of \(1 \mathrm{m} / \mathrm{s}\) produce?

Unlike the giant planets, the terrestrial planets formed when a. the inner Solar System was richer in heavy elements than the outer Solar System. b. the inner Solar System was hotter than the outer Solar System. c. the outer Solar System took up a bigger volume than the inner Solar System, so there was more material to form planets. d. the inner Solar System was moving faster than the outer Solar System.

Using the exoplanet catalogs: a. Go to the "Catalog" Web page (http://exoplanet.edu/ catalog) of the Extrasolar Planets Encyclopaedia and click on "All Planets detected." Look for a star (in the left column that has multiple planets. Make a graph showing the distances of the planets from their star, and note the masses and sizes of the planets. Put the Solar System planets on the same axis. How does this extrasolar planet system compare with the Solar System? b. Go to the "Exoplanets Data Explorer" website (http:// exoplanets.org \(),\) and click on "Table." This website lists planets that have detailed orbital data published in scientific journals, and it may have a smaller total count than the site in (a). Pick a planet that was discovered this year or last, as specified in the "First Reference" column. What is the planet's minimum mass? What is its semimajor axis and the period of its orbit? Is its orbit circular or more elliptical? Click on the star name in the first column to get more information. Is there a radial velocity curve for this planet? Was it observed in transit, and if so, what is the planet's radius and density? Is it more like Jupiter or more like Earth?

5\. Which of the following planets still has its primary atmosphere? a. Mercury b. Earth c. Mars d. Jupiter

T/F: Microlensing is similar to the transit method in that both require the planet to pass in front of a bright object.
See all solutions

Recommended explanations on Physics Textbooks

Magnetism and Electromagnetic Induction

Read Explanation

Further Mechanics and Thermal Physics

Read Explanation

Electrostatics

Read Explanation

Conservation of Energy and Momentum

Read Explanation

Measurements

Read Explanation

Fields in Physics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free