What are two kinds of information that astronomers can collect from stars by using spectrographs?

Answer 1

All elements have their own discrete power spectra. To excite a hydrogen atom requires a different amount of energy than to excite a helium atom. The energy of a photon is proportional to its wavelength. So by looking at the wavelengths in the absorption or emission lines in the spectra and comparing them to known energy levels (empirical or quantum mechanic derived) of different elements, a great deal can be said about a stars outer layer.

Answer 2

That depends on the band that they are observing. Optical, xray, and radio spectroscopy all yield differnet information about the light source when observed. Optical, for instance, can be used to study the doplar shift(red shiift) of a star or galaxy to determine its speed and direction relative to us. It can also yield information as to the elemental make up of the start. All matter emits electromagnetic radiation, and at specfic wavelengths throughout the EM Band. In the optical band, each element can be identified by its marker in the spectum.

Answer 3

They tell us the chemical composition of the stars.

Answer 4

Particular chemical "species". They can detect atoms, ions, even molecules in the cooler stars.

Answer 5

Each element has a characteristic "fingerprint" of absorption/emission lines, and the pattern of lines tells scientists which elements are present.

Answer 6

By comparing laboratory spectra of different gasses with dark lines in the solar spectrum, it is possible to identify the elements that make up the outer layer.

Answer 7

To my knowledge you get a variety of colours and those colours represent elements the star us made up of

Answer 8

compositions and temperatures