Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Capricornus [1] |
Right ascension | 20h 41m 54.6336s [2] |
Declination | −27° 12′ 57.415″ [2] |
Apparent magnitude (V) | 9.15±0.02 [3] |
Characteristics | |
Evolutionary stage | main sequence [2] |
Spectral type | G3 V [4] |
U−B color index | +0.30 [5] |
B−V color index | +0.65 [3] |
Astrometry | |
Radial velocity (Rv) | −43.9±0.3 [6] km/s |
Proper motion (μ) | RA: +175.628 [2] mas/yr Dec.: −15.593 [2] mas/yr |
Parallax (π) | 12.7715±0.0164 mas [2] |
Distance | 255.4 ± 0.3 ly (78.3 ± 0.1 pc) |
Absolute magnitude (MV) | 4.74 [1] |
Details | |
Mass | 0.97 [7] M☉ |
Radius | 1.08+0.07 −0.05 [8] R☉ |
Luminosity | 1.19 [1] L☉ |
Surface gravity (log g) | 4.40±0.02 [9] cgs |
Temperature | 5718±5 [9] K |
Metallicity [Fe/H] | −0.020±0.005 [9] dex |
Rotational velocity (v sin i) | 1.78±0.12 [9] km/s |
Age | 6.92±0.69 [9] Gyr |
Other designations | |
CD−27°14976, CPD−27°7079, HD 197027, HIP 102152, SAO 189585 [10] | |
Database references | |
SIMBAD | data |
HD 197027 (HIP 102152) is a star in the constellation Capricornus. It has an apparent magnitude of 9.15, [3] making it readily visible through a telescope but not to the naked eye. The object is located at a distance of 255 light years but is approaching the Solar System with a heliocentric radial velocity of −44 km/s . [6]
HD 197027 has a stellar classification of G3 V, indicating that it is an ordinary G-type main-sequence star like the Sun. It has only 97% the mass of the Sun [7] but 108% of its radius. [8] It shines at 119% the luminosity of the Sun [1] from its photosphere at an effective temperature of 5,718 K, [9] similar to the Sun's 5,778 K. HD 197027's metallicity – elements heavier than helium – is similar to the Sun. [9] At an older age of 6.92 billion years, it spins with a projected rotational velocity of about 2 km/s . [9]
Since its measured properties of this star are very similar to those of the Sun, it has been considered a candidate older solar twin. [11] The abundances of 21 elements overall are more similar to the Sun than any other known solar twin. [ citation needed ] Its Iron Abundance is −0.03 with an error value of 0.02 Fe/H. (The value comes from the Hipparcos Extended Catalog.) [12]