19 Cephei is a supergiant star in the northern circumpolar constellation of Cepheus. It has a spectral class of O9 and is a member of Cep OB2, an OB association of massive stars located about 615 parsecs (2,010 ly) from the Sun.
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 05m 08.78995s[1] |
| Declination | +62° 16′ 47.3301″[1] |
| Apparent magnitude (V) | 5.08[2] |
| Characteristics | |
| Spectral type | O9Ib[3] |
| U−B color index | −0.91[2] |
| B−V color index | +0.06[2] |
| Astrometry | |
| Radial velocity (Rv) | −12.8±0.9[4] km/s |
| Proper motion (μ) | RA: −1.16[1] mas/yr Dec.: −2.96[1] mas/yr |
| Parallax (π) | 1.58 ± 0.19 mas[1] |
| Distance | 1,200[5] pc |
| Absolute magnitude (MV) | −5.45[6] |
| Details | |
| Mass | 20[7] M☉ |
| Radius | 17.0[3] R☉ |
| Luminosity | 224,000[3] L☉ |
| Surface gravity (log g) | 3.40±0.08[8] cgs |
| Temperature | 32,983±1,428[8] K |
| Metallicity [Fe/H] | 0.06±0.08[8] dex |
| Rotational velocity (v sin i) | 48[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
The spectrum of 19 Cephei shows line profile variability on an hourly and daily timescale. This is thought to be due to the changes in the stellar wind.[3]
Double star catalogues list several companions for 19 Cephei. The Washington Double Star Catalog describes four companions: 11th magnitude stars 20" and 56" away, and two 15th magnitude stars 4-5" away.[9] The Catalog of Components of Double and Multiple Stars gives only the two 11th magnitude stars.[10]
A scattered cluster of faint stars has been detected associated with 19 Cephei. The brightest likely members apart from 19 Cep itself are 10th magnitude stars.[11]