TZ Cassiopeiae was reported as being variable by Williamina Fleming and published posthumously in 1911.[11] It is a slow irregular variable star with a possible period of 3,100 days.[12] It is over 90,000 times the luminosity of the Sun, and it is 767 times larger than the Sun. It is a member of the Cas OB5 stellar association, together with the nearby red supergiant PZ Cassiopeiae.[13]
The initial mass of TZ Cassiopeiae has been estimated from its position relative to theoretical stellar evolutionary tracks to be around 15 M☉.[14]
TZ Cas is losing mass through a powerful stellar wind at two millionths of a solar mass each year.[15] It is unclear whether this is sufficient to cause the star to lose its atmosphere and become a blue supergiant before the core exhausts its fuel and collapses as a supernova. Either as a red or blue supergiant, or a Wolf–Rayet star, it will inevitably end its life violently in a supernova explosion when the core collapse occurs.[16]
