Kepler-18
Kepler-18 is a star with almost the same mass as the Sun in the Cygnus constellation with 3 confirmed planets, announced in 2011.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 52m 19.0688s[1] |
| Declination | +44° 44′ 46.808″[1] |
| Apparent magnitude (V) | 14.0 |
| Characteristics | |
| Spectral type | G7 |
| Astrometry | |
| Proper motion (μ) | RA: −1.432±0.031[1] mas/yr Dec.: −20.313±0.028[1] mas/yr |
| Parallax (π) | 2.2804 ± 0.0168[1] mas |
| Distance | 1,430 ± 10 ly (439 ± 3 pc) |
| Details[2] | |
| Mass | 0.972 ± 0.042 M☉ |
| Radius | 1.108 ± 0.051 R☉ |
| Luminosity | 0.93 L☉ |
| Surface gravity (log g) | 4.32 ± 0.12 cgs |
| Temperature | 5383 ± 44 K |
| Metallicity [Fe/H] | 0.19 ± 0.06 dex |
| Rotational velocity (v sin i) | <4 km/s |
| Age | 10.0 ± 2.3 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Extrasolar Planets Encyclopaedia | data |
Planetary system
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 6.9 ± 3.4 M⊕ | 0.0447 ± 0.0006 | 3.504725 ± 0.000028 | — | 84.92 ± 0.26° | 2.00 ± 0.10 R⊕ |
| c | 17.3 ± 1.9 M⊕ | 0.0752 ± 0.0011 | 7.64159 ± 0.00003 | — | 87.68 ± 0.22° | 5.49 ± 0.26 R⊕ |
| d | 16.4 ± 1.4 M⊕ | 0.1172 ± 0.0017 | 14.85888 ± 0.00004 | — | 88.07 ± 0.1° | 6.98 ± 0.33 R⊕ |
gollark: A giant space rock would be very hard-pressed to destroy the Earth.
gollark: Depends on what you consider "die", but it will probably involve the sun doing things.
gollark: I mean, outside-view-ishly, life on Earth has existed for several billion years, so the probability (without knowing anything else) of it randomly stopping over the course of some arbitrary thousand or so is... not high.
gollark: > There's nothing that says that life on earth will go on forever. That the environment will not self destruct via CO2 and warming, or any other method.???
gollark: It's ethical™ because journals don't pay the scientists for them anyway.
References
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia Data Release 2 catalog entry
- Cochran, William D.; et al. (2011). "Kepler 18-b, c, and d: A System Of Three Planets Confirmed by Transit Timing Variations, Lightcurve Validation, Spitzer Photometry and Radial Velocity Measurements". The Astrophysical Journal Supplement Series. 197: 7. arXiv:1110.0820. Bibcode:2011ApJS..197....7C. doi:10.1088/0067-0049/197/1/7.
- "Kepler-18". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 25 January 2018.
External links
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