Coloured Filters & Spectroscopy PDF

# Coloured Filters Cooler stars emit most of their energy in infrared and visible parts of the spectrum; appear red to your eyes. Very hot stars emit a lot of energy in the visible violet and ultraviolet part of the spectrum and appear blue. ## Spectrometer Spectrometer measures starlight; splits...

# Coloured Filters Cooler stars emit most of their energy in infrared and visible parts of the spectrum; appear red to your eyes. Very hot stars emit a lot of energy in the visible violet and ultraviolet part of the spectrum and appear blue. ## Spectrometer Spectrometer measures starlight; splits light into a spectrum to reveal its component colours. ## Distinctive Lines Distinctive lines that appear in its spectrum determine what chemical elements are present in a star. When studying the spectra from stars, dark lines show missing colours. These "Fraunhofer lines" are due to light interacting with atoms in the outer layers of the star; the light energy is absorbed by electrons in atoms of all the elements in the outer gas layers. The absorption occurs at exactly the same wavelength that the element would emit when it's extremely hot. ## Spectral Class Spectral class is a classification system created from using spectra from different stars; it indicates the elements present in the star, the temperature and colour a star. ## Nuclear Fusion According to spectral analysis indicates that three-quarters of a star is helium, the rest is helium and oxygen and heavy elements. The enormous gravitational forces within a star.