HD 204521
G-type metal poor star in the constellation Cepheus
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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.[1] It is located at a distance of 86 light years from the Sun based on parallax, and has an absolute magnitude of 5.15.[1] The star is drifting closer with a radial velocity of −77 km/s,[1] and is predicted to come to within 7.96 light-years in 334,000 years.[5] At that distance the star can have a relatively small perturbing effect on comets in the Oort cloud.[9]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Cepheus[1] |
| Right ascension | 21h 25m 16.79696s[2] |
| Declination | +70° 28′ 39.1434″[2] |
| Apparent magnitude (V) | 7.26[1] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | G0V[3] |
| B−V color index | 0.619±0.015[1] |
| Astrometry | |
| Radial velocity (Rv) | −76.78±0.12[2] km/s |
| Proper motion (μ) | RA: +40.632[2] mas/yr Dec.: +39.411[2] mas/yr |
| Parallax (π) | 37.9375±0.0155 mas[2] |
| Distance | 85.97 ± 0.04 ly (26.36 ± 0.01 pc) |
| Absolute magnitude (MV) | 5.15[1] |
| Details | |
| Mass | 0.77±0.03[4] or 0.997[5] M☉ |
| Radius | 0.92[2] R☉ |
| Luminosity | 0.76[2] L☉ |
| Surface gravity (log g) | 4.43±0.02[4] cgs |
| Temperature | 5,699±50[4] K |
| Metallicity [Fe/H] | −0.75±0.05[4] dex |
| Rotational velocity (v sin i) | 3.6[6] km/s |
| Age | 8.43±4.24[7] Gyr |
| Other designations | |
| BD+69°1169, GJ 4194, HD 204521, HIP 105766, SAO 10045, TYC 4465-1133-1[8] | |
| Database references | |
| SIMBAD | data |
This is an ordinary G-type main-sequence star with a stellar classification of G0V,[3] indicating that it is generating energy through core hydrogen fusion. It is roughly 8 billion years old[7] and appears metal-deficient.[10] 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.[4]