24 Cephei is a single,[10] yellow-hued star in the northern circumpolar constellation of Cepheus. With an apparent visual magnitude of 4.79,[2] it is faintly visible to the naked eye. The distance to this star, based upon an annual parallax shift of 8.3965 mas,[1] is around 388 light years. It is moving closer with a heliocentric radial velocity of −17 km/s.[4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cepheus |
Right ascension | 22h 09m 48.43010s[1] |
Declination | +72° 20′ 28.3421″[1] |
Apparent magnitude (V) | 4.79[2] |
Characteristics | |
Spectral type | G7 II-III[3] |
B−V color index | 0.898[4] |
Astrometry | |
Radial velocity (Rv) | −16.58[4] km/s |
Proper motion (μ) | RA: +33.214[1] mas/yr Dec.: +2.679[1] mas/yr |
Parallax (π) | 8.3965 ± 0.1332 mas[1] |
Distance | 388 ± 6 ly (119 ± 2 pc) |
Absolute magnitude (MV) | −0.519[4] |
Details | |
Mass | 3.50[5] M☉ |
Radius | 13[6] R☉ |
Luminosity | 209[5] L☉ |
Surface gravity (log g) | 2.31±0.33[7] cgs |
Temperature | 5,023±54[7] K |
Metallicity [Fe/H] | −0.16±0.11[7] dex |
Rotational velocity (v sin i) | 6.5[8] km/s |
Age | 234[5] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Keenan and McNeil (1989) listed a stellar classification of G7 II-III[3] for 24 Cep, matching the spectrum of an evolved G-type star with blended features of a bright giant and a giant star. Older sources list a class of G8 III,[11] which would suggest an ordinary giant star. At the age of 234 million years,[5] it has an estimated 3.5[5] times the mass of the Sun and has expanded to about 13[6] times the Sun's radius. The star is radiating 199[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,023 K.[7] These coordinates are a source of X-ray emission.[12]