| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h 25m 00.0428s[2] |
| Declination | +49° 13′ 54.631″[2] |
| Apparent magnitude (V) | 11.9 |
| Characteristics | |
| Spectral type | G1IV |
| Astrometry | |
| Proper motion (μ) | RA: 1.151(11)mas/yr[2] Dec.: −8.064(11)mas/yr[2] |
| Parallax (π) | 1.8528±0.0087 mas[2] |
| Distance | 1,760 ± 8 ly (540 ± 3 pc) |
| Details | |
| Mass | 1.071±0.043[3] M☉ |
| Radius | 1.626±0.019[3] R☉ |
| Surface gravity (log g) | 4.1±0.1[4] cgs |
| Temperature | 5911±66[3] K |
| Metallicity[Fe/H] | −0.2±0.06[3] dex |
| Rotation | 17.20±0.2[3] |
| Rotational velocity (v sin i) | 4.9±1.0[3] km/s |
| Other designations | |
| Gaia DR2 2129931456691176576,KOI-277,KIC 11401755,2MASS J19250004+4913545[5] | |
| Database references | |
| SIMBAD | data |
| KIC | data |
Kepler-36 is a star in the constellation of Cygnus with two known planets. It has an anomalously large radius, meaning that it is asubgiant.
On June 21, 2012, the discovery of two planets orbiting the star was announced. The planets, asuper-Earth and a "mini-Neptune", are unusual in that they have very close orbits; theirsemi-major axes differ by only 0.013AU. The outer planet orbits only 11% farther than the inner one. Coupled with masses significantly higher than Earth, their gravitational influence to each other is significant, meaning that their interaction causes extremetransit timing variations for both. Kepler-36b and c have estimated densities of 6.8 and 0.86 g/cm3, respectively.[3] The two planets are close to a 7:6orbital resonance.[3] The large difference in densities, despite the close proximity of the planets' orbits, is likely due to the large difference in mass.[6] The innermost and less massive planet likely lost most, or all, of the hydrogen/helium envelope acquired during formation.
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 3.83+0.11 −0.10 M🜨 | 0.1153 | 13.86821±0.00049 | <0.04 | 90.0° | 1.498+0.061 −0.049 R🜨 |
| c | 7.13±0.18 M🜨 | 0.1283 | 16.21865±0.00010 | <0.04 | 90.0° | 3.679+0.096 −0.091 R🜨 |
2012 in space | ||
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