| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 26m 42.40624s[1] |
| Declination | +78° 47′ 09.0725″[1] |
| Apparent magnitude (V) | 5.84[2] |
| Characteristics | |
| Spectral type | A2m[3] |
| B−V color index | −0.16[2] |
| Astrometry | |
| Proper motion (μ) | RA: −13.33[1] mas/yr Dec.: −36.95[1] mas/yr |
| Parallax (π) | 15.83 ± 0.23 mas[1] |
| Distance | 206 ± 3 ly (63.2 ± 0.9 pc) |
| Details | |
| ρ1 Cep A | |
| Mass | 2.00[3] M☉ |
| Rotational velocity (v sin i) | 81[4] km/s |
| Age | 320[3] Myr |
| ρ1 Cep B | |
| Mass | 0.51[3] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Rho1 Cephei (ρ1 Cephei) is a double star located in the northern constellation of Cepheus. As of 2014, the pair had an angular separation of 0.29 arc seconds along a position angle of 211.1°. This corresponds to a projected separation of 18.1 AU.[3] Rho1 Cephei is faintly visible to the naked eye with an apparent visual magnitude of 5.84,[2] and it forms an optical pair with the brighter star Rho2 Cephei. Based upon an annual parallax shift of 15.83 mas as seen from the Earth,[1] Rho1 Cephei is located about 206 light years from the Sun.
The primary component is a chemically peculiar Am star with a stellar classification of A2m.[3] It has twice the mass of the Sun and is around 320 million years old.[3] The smaller companion may be the source of the X-ray emission from this location, as stars similar to the primary component do not generally produce detectable levels of X-rays.[6]
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