An astronomer records the spectrum of light coming from a distant star. Describe what information ...

Answer to q. 1

The spectrum of light from a star will be an absorption spectrum.

The astronomer can examine the continuous radiation in the spectrum to determine the wavelength of peak intensity. Using Wien's law, this will enable the astronomer to determine the surface temperature of the star.

The absorption spectrum will contain isolated regions where the intensity of the spectrum is very low. These will appear as dark lines on a photographic spectrum. These lines are caused by the absorption of photons from electrons becoming excited to higher energy levels. By comparing the pattern of wavelengths of the dark lines with known values, the astronomer will be able to determine the chemical composition of the cool gas in the atmosphere of the star since each element has its own unique pattern of energy levels and absorption/emission lines.

The entire absorption spectrum pattern may be shifted towards the red or blue end of the spectrum. This is caused by motion of the star toward or away from the observer, and is explained by the Doppler effect.

Answer to q. 2

The core of a Seyfert galaxy is extremely luminous. The luminosity of the core fluctuates quickly and randomly.

Answer to q. 3

Blackbody radiation creates a continuous spectrum of photons at different wavelengths. When these photons pass through a cool gas, some are absorbed as they excite atoms in the gas. An observer on the other side then sees a continuum of photons with gaps at certain wavelengths - an absorption spectrum.

Answer to q. 4

collisions
interactions
collision
interaction
merger
mergers

Answer to q. 5

An electron will move from one energy level to another if enough energy is added to the electron. An electron in a low energy level can absorb the energy of a photon and move to a higher energy level.

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It really depends on the course, never give up