HD 204521
Location of HD 204521; not visible on this chart, but just to the west of β Cephei (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 21h 25m 16.79696s |
| Declination | +70° 28′ 39.1434″ |
| Apparent magnitude (V) | 7.26 (binoculars) |
| Characteristics | |
| Spectral type | G0V |
| B−V color index | 0.619±0.015 |
| Astrometry | |
| Radial velocity (Rv) | −76.78±0.12 km/s |
| Proper motion (μ) | RA: +40.632 mas/yr Dec.: +39.411 mas/yr |
| Parallax (π) | 37.9375±0.0155 mas |
| Distance | 85.97 ± 0.04 ly (26.36 ± 0.01 pc) |
| Absolute magnitude (MV) | 5.15 |
| Details | |
| Mass | 0.77±0.03 or 0.997 M☉ |
| Radius | 0.92 R☉ |
| Luminosity | 0.76 L☉ |
| Surface gravity (log g) | 4.43±0.02 cgs |
| Temperature | 5,699±50 K |
| Metallicity [Fe/H] | −0.75±0.05 dex |
| Rotational velocity (v sin i) | 3.6 km/s |
| Age | 8.43±4.24 Gyr |
| Other designations | |
| BD+69°1169, GJ 4194, HD 204521, HIP 105766, SAO 10045, TYC 4465-1133-1 | |
| Database references | |
| SIMBAD | data |
HD 204521 is a star in the northern constellation of Cepheus. In the sky it positioned just to the west of the magnitude 3.2 star Beta Cephei (β Cep). This object has a yellow hue similar to the Sun but is too faint to be visible to the naked eye with an apparent visual magnitude of 7.26. It is located at a distance of 86 light years from the Sun based on parallax, and has an absolute magnitude of 5.15. The star is drifting closer with a radial velocity of −77 km/s, and is predicted to come to within 7.96 light-years in 334,000 years. At that distance the star can have a relatively small perturbing effect on comets in the Oort cloud.
This is an ordinary G-type main-sequence star with a stellar classification of G0V, indicating that it is generating energy through core hydrogen fusion. It is roughly 8 billion years old and appears metal-deficient. The mass of this star appears to be at or below that of the Sun, and it is radiating 76% of the Sun's luminosity from its photosphere at an effective temperature of 5,699 K.