A-Type Main-Sequence Stars

Hot white and blue-tinged white stars of spectral type A that shine by fusing hydrogen in their cores, such as Vega in Lyra and Altair in Aquila, two of the three stars of the Summer Triangle. A star belongs here when its cited article classifies it as an A-type main-sequence star. It excludes red dwarfs, red giants and supergiants, and evolved or giant stars of any colour. Because these stars are hot, luminous and fairly short lived by stellar standards, they make convenient reference points for brightness scales and for studies of stellar rotation, dust discs and the way hydrogen fusion shapes a star over time.