Line broadening

Definition

Line broadening is the phenomenon where spectral lines from astronomical objects are wider than expected. This occurs due to various factors such as thermal motion, rotation, and magnetic fields.

5 Must Know Facts For Your Next Test

1. Thermal Doppler broadening results from the random motion of particles in a hot gas.
2. Rotational broadening occurs when different parts of a galaxy rotate at different speeds, causing a spread in observed wavelengths.
3. Turbulence within interstellar gas clouds also contributes to line broadening.
4. Zeeman splitting causes line broadening when magnetic fields affect the energy levels of electrons in atoms.
5. Line broadening can provide insights into the physical conditions and dynamics within galaxies.

Review Questions

• What are the main causes of line broadening in astronomical observations?
• How does rotational motion within a galaxy contribute to line broadening?
• Explain how Zeeman splitting affects spectral lines.

Related terms

Doppler Effect:

The change in frequency or wavelength of light from an object moving relative to an observer.

Spectral Line: A dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light.

Zeeman Effect: The splitting of a spectral line into several components in the presence of a static magnetic field.