Chapter 24, Problem 1CC

To determine

The two major differences between a spectrum of a star and that of a quasar.

Answer to Problem 1CC

Solution:

The spectrum of a star bears absorption lines, whereas the spectrum of a quasar is dominated by emission lines. Besides, the Doppler shifts for quasars are much higher as compared to that of the stars in the galaxies, for both absorption and emission spectra. Also, the emission at the radio or X-ray wavelengths of a quasar is stronger as compared to a star.

Explanation of Solution

Introduction:

Spectrum can be defined as the range of the colors that are obtained by passing sunlight through a glass prism. A spectrum radiated from the celestial objects like quasars or stars can be detected and studied in astronomy.

Explanation:

Quasars are “star-like” point sources of light exhibiting larger red-shifts and immense energy. On the other hand, stars are the “self-illuminating” celestial objects that have lower energy outputs, as compared to the quasars.

One of the major differences between stars and quasars is that the spectrum lines of the quasars are usually dominated by emission lines, whereas the spectral lines of stars show absorption lines.

Another difference between the spectrum of stars and quasars can be explained through their Doppler shifts. The shifts exhibited by quasars are quite larger than those exhibited by stars, and quasars show larger red-shifts as well. This can be attributed to the fact that quasars can recede faster as compared to stars.

A quasar has the ability to emit stronger radiations at X-ray and radio wavelengths, compared to a star.

Conclusion:

Therefore, stars and quasars are similar celestial objects with some major differences. One of the contrasting traits between them lies in their spectrum, where the former shows absorption lines and the latter does not.