An A-type main-sequence star is a type of star that falls within the spectral classification of A. These stars are characterized by their white to blue-white color and have surface temperatures ranging from about 7,500 to 10,000 Kelvin. They are more massive than the Sun and typically have a mass between 1.5 and 2.5 times that of our star. A-type stars are known for their strong hydrogen absorption lines in their spectra. A-type main-sequence stars are often found in open star clusters and can be relatively short-lived, with lifespans of around 1 to 2 billion years. They eventually evolve into giant stars as they exhaust their hydrogen fuel. Examples of A-type stars include Sirius A and Altair, which are among the brightest stars visible from Earth.