An A-type star is a classification of stars that are typically white or bluish in color. They have surface temperatures ranging from about 7,500 to 10,000 degrees Celsius. A-type stars are known for their strong hydrogen absorption lines in their spectra, which makes them distinct from other types of stars. They are often more massive than the Sun and can be found in various stages of their life cycle. These stars are usually part of the main sequence, where they spend most of their lives fusing hydrogen into helium. Examples of A-type stars include Sirius A and Altair. Due to their brightness, A-type stars can often be seen from Earth, making them important for astronomical studies.