Based upon parallax measurements made by the Hipparcos satellite, it is located at a distance of roughly 550 light-years from Earth.

[14] Gamma Cassiopeiae is an eruptive variable star, whose apparent magnitude changes irregularly from 1.6 at its brightest to 3.0 at its dimmest.

Gamma Cassiopeiae is a rapidly spinning star with a projected rotational velocity of 472 km s−1, giving it a pronounced equatorial bulge.

When combined with the star's high luminosity, the result is the ejection of matter that forms a hot circumstellar disk of gas.

The 'e' suffix is used for stars that show emission lines of hydrogen in the spectrum, caused in this case by the circumstellar disk.

Gamma Cassiopeiae is the prototype of a small group of stellar sources of X-ray radiation that is about 10 times stronger than emitted from other B or Be stars.

The character of the X-ray spectrum is Be thermal, possibly emitted from plasmas of temperatures up to least ten million kelvins, and shows very short term and long-term cycles.

For example, it is not clear that enough matter can be accreted by a white dwarf, at the distance of the purported secondary star implied by the orbital period, sufficient to power an X-ray emission of nearly 1033 erg/s or 100 YW.

This evidence suggests that a magnetic field from the star is interacting with the decretion disk, resulting in the X-ray emission.

However, difficulties remain with this mechanism, among which is that there are no disk dynamos known to exist in other stars, rendering this behavior more difficult to analyze.

[15] Gamma Cassiopeiae A, the bright primary, itself contains a spectroscopic binary with an orbital period of about 203.5 days and an eccentricity alternately reported as 0.26 and "near zero."