| Term: | A stars |
| Definition: |
A star whose spectrum shows strong hydrogen Balmer lines accompanied by many faint to moderately strong metallic lines. In contrast to B and O stars, the lines of He I and He II are absent. Their surface temperature ranges from 7,500 to 10,000 K. The main metallic lines seen in A-type stars are those of Fe I and Fe II, Cr I and II, Ti I and II, and account for about two-thirds of all lines. Some famous examples of A star are Sirius, Deneb, Altair, and Vega. Also known as A-type star. |