Kappa Cassiopeiae


Kappa Cassiopeiae, also named Cexing, is a star in the constellation Cassiopeia. Its name is a Bayer designation that is Latinized from κ Cassiopeiae, and abbreviated Kappa Cas or κ Cas. This is a variable star of 4th magnitude, indicating it is visible to the naked eye.
κ Cassiopeiae is assumed to be a member of the Cassiopeia OB14 stellar association and treated as being at a distance of about, while its distance found from the Gaia parallax measurement is about. A 2020 determination of the distance to Cas OB14 is.

Nomenclature

Kappa Cassiopeiae is the star's Bayer designation.
In Chinese astronomy, κ Cassiopeiae is associated with the asterism Beta Cassiopeiae, representing a legendary charioteer from the Spring and Autumn period. It was originally identified as Cè, the charioteer's whip, but this name was later transferred to γ Cassiopeiae, with κ Cassiopeiae becoming one of the charioteer's four horses. The IAU Working Group on Star Names approved the name Cexing for κ Cassiopeiae on 13 November 2025 and it is now so entered in the IAU Catalog of Star Names; xing means star, and this form of the name was already used in ancient times.

Properties

κ Cassiopeiae has an unusual spectrum that has anomalously weak nitrogen lines, taken as an actual nitrogen deficiency in the atmosphere. This is indicated by the modified letter C on the assumption that it is also carbon-rich, although this might not actually be the case. It is also interpolated to BC0.7, being slightly hotter than a standard B1 star.
It is classified as an Alpha Cygni type variable star and its brightness varies by a few hundredths of a magnitude. Periods of two hours, 2.65 days, and nine days have been reported from observations at different times.
It is a runaway star. Its magnetic field and wind of particles creates a visible bow shock 4 light-years ahead of it, colliding with the diffuse, and usually invisible, interstellar gas and dust. This is about the same distance that Earth is from Proxima Centauri, the nearest star to the Sun. The dimensions of the bow shock are vast: around 12 light-years long and 1.8 light-years wide.