GENERAL KNOWLEDGE

Detailed explanation-1: -A stellar spectrum can reveal many properties of stars, such as their chemical composition, temperature, density, mass, distance and luminosity. Spectroscopy can show the velocity of motion towards or away from the observer by measuring the Doppler shift.

Detailed explanation-2: -When they are moving relative to each other, the lines will appear shifted. For example, if a star is moving toward us, its lines will be observed at shorter wavelengths, which is called “blueshifted". If the star is moving away from us, the lines will appear at longer wavelengths, which is called “redshifted".

Detailed explanation-3: -Most stars emit the bulk of their electromagnetic energy as visible light, that sliver of the spectrum our eyes can see. Hotter stars emit higher energy light, so the color of the star indicates how hot it is. This means that red stars are cool, while blue stars are hot.

Detailed explanation-4: -The most common method astronomers use to determine the composition of stars, planets, and other objects is spectroscopy. Today, this process uses instruments with a grating that spreads out the light from an object by wavelength.