HD 97658
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Leo[1] |
| Right ascension | 11h 14m 33.1613s[2] |
| Declination | +25° 42′ 37.392″[2] |
| Apparent magnitude (V) | 7.762±0.012[3] |
| Characteristics | |
| Evolutionary stage | Main sequence[4] |
| Spectral type | K1V[5] |
| B−V color index | 0.843±0.022[3] |
| Variable type | Planetary transit variable |
| Astrometry | |
| Radial velocity (Rv) | −1.579±0.0011[6] km/s |
| Proper motion (μ) | RA: −107.534±0.091[2] mas/yr Dec.: 48.662±0.090[2] mas/yr |
| Parallax (π) | 46.412 ± 0.022[7] mas |
| Distance | 70.27 ± 0.03 ly (21.55 ± 0.01 pc) |
| Absolute magnitude (MV) | 6.14[8] |
| Details | |
| Mass | 0.773+0.015 −0.018[7] M☉ |
| Radius | 0.728±0.008[7] R☉ |
| Luminosity (bolometric) | 0.351±0.007[7] L☉ |
| Surface gravity (log g) | 4.52 ± 0.06[3] cgs |
| Temperature | 5212±43[7] K |
| Metallicity [Fe/H] | −0.30±0.03[3] dex |
| Rotation | 38.5±1.0[3] |
| Rotational velocity (v sin i) | 0.92±0.05[3] km/s |
| Age | 3.9+2.6 −2.03[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 97658 is a star with an exoplanetary companion in the equatorial constellation of Leo. The star is too dim to be seen with the naked eye, having an apparent visual magnitude of 7.76.[3] It is located at a distance of 70 light years based on parallax, but is slowly drifting closer with a radial velocity of −1.6 km/s.[6]
This is an ordinary K-type main-sequence star with a stellar classification of K1V.[5] The star has 77% of the mass and 73% of the radius of the Sun.[7] Estimates of the star's age ranges from four to six billion years.[7] It is spinning with a rotation period of around 39 days[3] and shows a magnetic activity cycle of 9.6 years, which is slightly shorter than the solar cycle. The chromospheric activity is lower than average for stars of this class.[10]
HD 97658 is radiating 35% of the luminosity of the Sun from its photosphere at an effective temperature of 5,212 K.[7] The star has a low metallicity – the atmospheric abundance of elements with a higher atomic number than helium, which explains why it lies 0.46 magnitudes below average for main sequence stars of its type.[4]
Planetary system[]
On November 1, 2010, a super-Earth was announced orbiting the star along with Gliese 785 b as part of the NASA-UC Eta-Earth program. The planet orbits in just under 9.5 days and was originally thought to have a minimum mass of 8.2 ± 1.2 M