Stellar Spectra: The Colors of the Stars

A star’s spectrum is like its fingerprint, revealing temperature, composition, and motion.
Stellar spectra show dark absorption lines where elements absorb specific wavelengths of light.
Stars are classified into spectral types O, B, A, F, G, K, and M—ranging from hottest to coolest.
Our Sun is a G-type star, glowing with a yellowish light around 5,800 K.
Blue O-type stars can reach surface temperatures of over 30,000 K.
Red M-type stars are the coolest and most common in the universe.
Spectra reveal a star’s radial velocity by measuring Doppler shifts in its light.
Heavy elements in spectra prove that stars are cosmic forges, creating the building blocks of planets and life.
Cecilia Payne first showed that hydrogen and helium dominate stellar composition, revolutionizing astrophysics.
Stellar spectra let astronomers trace star lifecycles, galaxy evolution, and even search for exoplanets.