9 Cassiopeiae (9 Cas) is a white giant star in the constellation Cassiopeia, about 2,370 light years away.
9 Cassiopeiae is classified as an A1 type giant or bright giant. One study noted peculiarities in the spectrum that could indicate a λ Boötis star, but other researchers have refuted this.
At an age of 25 million years, 9 Cassiopeiae has expanded away from the main sequence after exhausting its core hydrogen and now has a radius about 26 times that of the Sun. With an effective temperature of about, it emits more than two thousand times the luminosity of the Sun.
9 Cassiopeiae has a number of faint companions listed in multiple star catalogues, but they all appear to be at different distances and none are thought to be gravitationally associated.