 Kepler-28 compared to the Sun | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19 28 32.8905 |
| Declination | +42° 25′ 45.959″ |
| Apparent magnitude (V) | 15.036 |
| Characteristics | |
| Spectral type | M0V |
| Astrometry | |
| Radial velocity (Rv) | −26.99±6.00 km/s |
| Proper motion (μ) | RA: −0.463(21) mas/yr Dec.: 11.691(21) mas/yr |
| Parallax (π) | 2.2537 ± 0.0185 mas |
| Distance | 1,450 ± 10 ly (444 ± 4 pc) |
| Details | |
| Mass | 0.684±0.026 M☉ |
| Radius | 0.664±0.013 R☉ |
| Temperature | 4499±75 K |
| Metallicity | −0.17±0.11 dex |
| Rotation | 17.951±0.016 days |
| Rotational velocity (v sin i) | 0.6 km/s |
| Age | 2.2 Gyr |
| Other designations | |
| KOI-870, KIC 6949607, 2MASS J19283288+4225459 | |
| Database references | |
| SIMBAD | data |
| KIC | data |
Kepler-28 is an M-type main-sequence star about 1,450 light-years (440 parsecs) away in the northern constellation of Cygnus. With an apparent visual magnitude of 15.036, this star is too faint to be seen with the naked eye. It is orbited by two exoplanets.
Planetary system
The two transiting planets of Kepler-28 were discovered in 2011 using the Kepler space telescope, and were confirmed in early 2012. They are both warm sub-Neptune gas planets. The planetary parameters were updated in 2023, with lower values for all of mass, radius, and density compared to previous estimates.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 1.63+0.51 −0.40 M🜨 |
0.062 | 5.91213(17) | <0.08 | — | 1.959+0.043 −0.042 R🜨 |
| c | 2.06+0.70 −0.52 M🜨 |
0.081 | 8.98597(27) | 0.017+0.023 −0.014 |
— | 1.857±0.042 R🜨 |
References
- "Cygnus – constellation boundary", The Constellations, International Astronomical Union, retrieved 2011-12-15
- ^ 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.
- ^ Kepler-28b, NASA Ames Research Center, archived from the original on 2012-05-03, retrieved 2011-12-06
- ^ Muirhead, Philip S.; Hamren, Katherine; et al. (May 2012). "Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars". The Astrophysical Journal Letters. 750 (2): L37. arXiv:1109.1819. Bibcode:2012ApJ...750L..37M. doi:10.1088/2041-8205/750/2/L37.
- ^ Leleu, A.; Delisle, J.-B.; et al. (January 2023). "Removing biases on the density of sub-Neptunes characterised via transit timing variations. Update on the mass-radius relationship of 34 Kepler planets". Astronomy & Astrophysics. 669: A117. arXiv:2207.07456. Bibcode:2023A&A...669A.117L. doi:10.1051/0004-6361/202244132.
- McQuillan, A.; Mazeh, T.; Aigrain, S. (2013). "Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators". The Astrophysical Journal Letters. 775 (1). L11. arXiv:1308.1845. Bibcode:2013ApJ...775L..11M. doi:10.1088/2041-8205/775/1/L11.
- ^ Cubillos, Patricio; Erkaev, Nikolai V.; Juvan, Ines; Fossati, Luca; Johnstone, Colin P.; Lammer, Helmut; Lendl, Monika; Odert, Petra; Kislyakova, Kristina G. (2016), "An overabundance of low-density Neptune-like planets", Monthly Notices of the Royal Astronomical Society, 466 (2): 1868–1879, arXiv:1611.09236, Bibcode:2017MNRAS.466.1868C, doi:10.1093/mnras/stw3103, S2CID 119408956
- "Kepler-28". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 January 2017.
- Steffen, Jason H.; Fabrycky, Daniel C.; Ford, Eric B.; Carter, Joshua A.; Desert, Jean-Michel; Fressin, Francois; Holman, Matthew J.; Lissauer, Jack J.; Moorhead, Althea V.; Rowe, Jason F.; Ragozzine, Darin; Welsh, William F.; Batalha, Natalie M.; Borucki, William J.; Buchhave, Lars A.; Bryson, Steve; Caldwell, Douglas A.; Charbonneau, David; Ciardi, David R.; Cochran, William D.; Endl, Michael; Everett, Mark E.; Gautier III, Thomas N.; Gilliland, Ron L.; Girouard, Forrest R.; Jenkins, Jon M.; Horch, Elliott; Howell, Steve B.; Isaacson, Howard; et al. (2012), Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations, arXiv:1201.5412, Bibcode:2012MNRAS.421.2342S, doi:10.1111/j.1365-2966.2012.20467.x, S2CID 11898578