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.[2] It is located at a distance of 86 light years from the Sun based on parallax, and has an absolute magnitude of 5.15.[2] The star is drifting closer with a radial velocity of −77 km/s,[2] 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.[8]

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 16.79707s[1]
Declination	+70° 28′ 39.1412″[1]
Apparent magnitude (V)	7.26[2] (binoculars)
Characteristics
Spectral type	G0V[3]
B−V color index	0.619±0.015[2]
Astrometry
Radial velocity (Rv)	−76.6±0.3[2] km/s
Proper motion (μ)	RA: +40.601[1] mas/yr Dec.: +39.564[1] mas/yr
Parallax (π)	37.9131 ± 0.0279 mas[1]
Distance	86.03 ± 0.06 ly (26.38 ± 0.02 pc)
Absolute magnitude (MV)	5.15[2]
Details
Mass	0.77±0.03[4] or 0.997[5] M☉
Luminosity	0.86[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
Age	8.43±4.24[6] Gyr
Other designations
BD+69°1169, GJ 4194, HD 204521, HIP 105766, SAO 10045, TYC 4465-1133-1[7]
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[6] billion years old and appears metal-deficient.[9] The mass of this star appears to be at or below that of the Sun, and it is radiating 86%[2] of the Sun's luminosity from its photosphere at an effective temperature of 5,699 K.[4]

References

External links

• Wikisky image of HD 204521 (HIP 105766)
• List of G stars within 100 light-years