Kappa Cassiopeiae
Star in the constellation Cassiopeia
From Wikipedia, the free encyclopedia
Kappa Cassiopeiae, also named Cexing,[12] 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,[3] indicating it is visible to the naked eye.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cassiopeia[1] |
| Right ascension | 00h 32m 59.992s[2] |
| Declination | +62° 55â² 54.41â³[2] |
| Apparent magnitude (V) | 4.12 to 4.21[3] |
| Characteristics | |
| Spectral type | BC0.7 Ia[4] |
| Apparent magnitude (U) | 3.50[5] |
| Apparent magnitude (B) | 4.276[5] |
| Apparent magnitude (J) | 4.141[5] |
| Apparent magnitude (H) | 4.148[5] |
| Apparent magnitude (K) | 4.013[5] |
| UâB color index | â0.776[5] |
| BâV color index | +0.0869[5] |
| JâH color index | â0.0069[5] |
| JâK color index | +0.128[5] |
| Variable type | α Cyg[6] |
| Astrometry | |
| Radial velocity (Rv) | 0.30[7] km/s |
| Proper motion (μ) | RA: +3.65 mas/yr[2] Dec.: â2.07 mas/yr[2] |
| Parallax (Ï) | 0.73±0.17 mas[2] |
| Distance | approx. 4,000 ly (approx. 1,400 pc) |
| Absolute magnitude (MV) | â7.1[8] |
| Details | |
| Mass | 33[9] Mâ |
| Radius | 39[8] Râ |
| Luminosity | 490,000[8] Lâ |
| Surface gravity (log g) | 2.79[8] cgs |
| Temperature | 24,600[8] K |
| Rotational velocity (v sin i) | 58[8] km/s |
| Age | 4.5[10] Myr |
| Other designations | |
| Cexing, κ Cas, 15 Cassiopeiae, BD+62°102, FK5 16, GC 645, HD 2905, HIP 2599, HR 130, SAO 11256[11] | |
| Database references | |
| SIMBAD | data |
κ Cassiopeiae is assumed to be a member of the Cassiopeia OB14 stellar association (Cas OB14) and treated as being at a distance of about 1,100 pc,[13] while its distance found from the Gaia parallax measurement is about 4,600 light-years (1,400 pc).[2] A 2020 determination of the distance to Cas OB14 is 880 pc.[14]
Nomenclature
Kappa Cassiopeiae (Latinized from κ Cassiopeiae) is the star's Bayer designation.
In Chinese astronomy, κ Cassiopeiae is associated with the asterism Wáng Liáng (çè¯), representing a legendary charioteer from the Spring and Autumn period. It was originally identified as Cè (ç), the charioteer's whip, but this name was later transferred to γ Cassiopeiae, with κ Cassiopeiae becoming one of the charioteer's four horses.[15][16] 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.[12]
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.[9] It is also interpolated to BC0.7, being slightly hotter than a standard B1 star.[18][13]
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,[19] 2.65 days,[20] and nine days[21] 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.[22] The dimensions of the bow shock are vast: around 12 light-years long and 1.8 light-years wide.[23]