Kepler-36
Kepler-36
Star in the constellation Cygnus
Kepler-36 is a star in the constellation of Cygnus with two known planets. It has an anomalously large radius, meaning that it is a subgiant.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 25m 00.0428s[1] |
| Declination | +49° 13′ 54.631″[1] |
| Apparent magnitude (V) | 11.9 |
| Characteristics | |
| Spectral type | G1IV |
| Astrometry | |
| Proper motion (μ) | RA: 1.151(11) mas/yr[1] Dec.: −8.064(11) mas/yr[1] |
| Parallax (π) | 1.8528 ± 0.0087 mas[1] |
| Distance | 1,760 ± 8 ly (540 ± 3 pc) |
| Details | |
| Mass | 1.071±0.043[2] M☉ |
| Radius | 1.626±0.019[2] R☉ |
| Surface gravity (log g) | 4.1±0.1[3] cgs |
| Temperature | 5911±66[2] K |
| Metallicity [Fe/H] | −0.2±0.06[2] dex |
| Rotation | 17.20±0.2[2] |
| Rotational velocity (v sin i) | 4.9±1.0[2] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| KIC | data |
On June 21, 2012, the discovery of two planets orbiting the star was announced. The planets, a super-Earth and a "mini-Neptune", are unusual in that they have very close orbits; their semi-major axes differ by only 0.013 AU. The outer planet orbits only 11% further than the inner one. Coupled with masses significantly higher than Earth, their gravitational influence to each other is significant, meaning that their interaction causes extreme transit timing variations for both. Kepler-36b and c have estimated densities of 6.8 and 0.86 g/cm3, respectively.[2] The two planets are close to a 7:6 orbital resonance.[2] The large difference in densities, despite the close proximity of the planets' orbits, is likely due to the large difference in mass.[5] 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🜨 |
- Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- Vissapragada, Shreyas; et al. (2020). "Diffuser-assisted Infrared Transit Photometry for Four Dynamically Interacting Kepler Systems". The Astronomical Journal. 159 (3). 108. arXiv:1907.04445. Bibcode:2020AJ....159..108V. doi:10.3847/1538-3881/ab65c8. S2CID 195874295.
- "Kepler-36". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-07.
- Bodenheimer, P.; Stevenson, D.; Lissauer, J.; D'Angelo, G. (2018). "New Formation Models for the Kepler-36 System". The Astrophysical Journal. 868 (2): id. 138 (17 pp.). arXiv:1810.07160. Bibcode:2018ApJ...868..138B. doi:10.3847/1538-4357/aae928. S2CID 59055335.