PH2
PH2, also known as Kepler-86, or KIC 12735740 (2MASS J19190326+5157453), is a G-type star 1,120 light-years (340 parsecs) distant within the constellation Cygnus. Roughly the size and temperature of the Sun, PH2 gained prominence when it was known to be the host of one of 42 planet candidates detected by the Planet Hunters citizen science project in its second data release. The candidate orbiting around PH2, known as PH2b, had been determined to have a spurious detection probability of only 0.08%, thus effectively confirming its existence as a planet.
Artist's conception of PH2 and its planet, PH2b, viewed from a hypothetical moon of the planet. Credit: Haven Giguere, Matthew Giguere/Yale | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 19m 03.26334s |
| Declination | +51° 57′ 45.4099″ |
| Apparent magnitude (V) | 12.699±0.010 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G5V |
| Apparent magnitude (J) | 11.501±0.023 |
| Apparent magnitude (H) | 11.182±0.03 |
| Apparent magnitude (K) | 11.116±0.022 |
| Apparent magnitude (B1) | 12.34 |
| Apparent magnitude (R1) | 12.62 |
| B−V color index | 0.072 |
| Astrometry | |
| Radial velocity (Rv) | −17.79±1.88 km/s |
| Proper motion (μ) | RA: 3.427 mas/yr Dec.: 16.047 mas/yr |
| Parallax (π) | 2.9134 ± 0.0105 mas |
| Distance | 1,120 ± 4 ly (343 ± 1 pc) |
| Absolute bolometric magnitude (Mbol) | 5.01+0.12 −0.12 |
| Details | |
| Mass | 0.958±0.034 M☉ |
| Radius | 0.961+0.016 −0.015 R☉ |
| Luminosity (bolometric) | 0.79+0.09 −0.08 L☉ |
| Surface gravity (log g) | 4.45±0.02 cgs |
| Temperature | 5711+60 −59 K |
| Metallicity [Fe/H] | −0.03±0.04 dex |
| Rotation | 22.6 days |
| Rotational velocity (v sin i) | 1.43±0.78 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| KIC | data |
Located in its parent star's habitable zone, PH2b (or Kepler-86b) is a Jupiter-size gas giant which could in theory host a natural satellite suitable for hosting life. The report of the confirmed detection of PH2b was submitted on January 3, 2013. It was discovered by amateur Pole Rafał Herszkowicz using his laptop and access to the Internet project with data from the Kepler space observatory.