盾牌座δ
Theta Tucanae is a white A-type subgiant of spectral type A7IV with a mean apparent magnitude of +6.11, located approximately 423 light years from Earth. It is classified as a Delta Scuti type variable star and its brightness varies from magnitude +6.06 to +6.15 with periods of around 70 to 80 minutes. The Delta Scuti variables are a class of short-period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology.