Theta Tucanae is a white A-type star around 423 light-years distant from Earth, which is actually a close binary system. The main star is classified as a Delta Scuti variable—a class of short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study asteroseismology. It is around double the Sun's mass, having siphoned off one whole solar mass from its companion, now a hydrogen-depleted dwarf star of around only 0.2 solar masses. The system shines with a combined light that varies between magnitudes 6.06 to 6.15 every 70 to 80 minutes.