MZ Cassiopeiae

MZ Cassiopeiae is a red supergiant star in the constellation of Cassiopeia. It is located $-3.447$ away from Earth, and is a member of Cassiopeia OB4.

MZ Cas has an effective temperature of $-0.995$, a luminosity of $7,690$, and a radius of $2,360$. It is an oxygen-rich star, losing mass at a rate of $600$ per year. The star has a spectral type of M2Ia-Iab, and is listed in the GCVS as a slow irregular variable of type Lc. MZ Cas varies in apparent magnitude from 9.13 at maximum to 10.32 at minimum with no identified period.

The excess spectrum of MZ Cas displays emission in the unidentified infrared (UIR)-band at 8.65 μm and 11.3 μm, as well as a weaker feature at 12.6 μm. The former has been attributed to carbonaceous species such as polycyclic aromatic hydrocarbons. Previous studies found the star to display a 11.5 μm feature, which the authors attributed to silicon carbide (SiC). They concluded that MZ Cas, along with AD Per which displayed a similar feature, might be the first S-type supergiants to be identified. However, the stars were later found to not be SiC-emission sources.