Kepler-11
 Artist's conception of a simultaneous transit of three planets before Kepler-11 observed by NASA's Kepler spacecraft on Aug. 26, 2010. |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 48m 27.622s |
| Declination | +41° 54′ 32.87″ |
| Apparent magnitude (V) | 14.2 |
| Astrometry | |
| Proper motion (μ) |
RA: –0.7 mas/yr Dec.: –4.1 mas/yr |
| Distance | 613pc |
| Characteristics | |
| Spectral type | G6V |
| Details | |
| Mass |
0.961+0.025 −0.025 M☉ |
| Radius |
1.065+0.017 −0.022 R☉ |
| Luminosity |
1.045+0.061 −0.078 L☉ |
| Surface gravity (log g) |
4.366+0.014 −0.016 cgs |
| Temperature |
5663+55 −66 K |
| Metallicity [Fe/H] | 0 (± 0.1) dex |
| Age |
8.5+1.1 −1.4 Gyr |
| Other designations | |
Kepler-11 is a Sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars. Announced on February 2, 2011, the star system is among the most compact and flattest systems yet discovered. It is the first discovered case of a star system with six transiting planets. All discovered planets are larger than Earth, with the larger ones being about Neptune's size.
Kepler-11 and its planets were discovered by NASA's Kepler Mission, a mission tasked with discovering planets in transit around their stars. The transit method that Kepler uses involves detecting dips in brightness in stars. These dips in brightness can be interpreted as planets whose orbits move in front of their stars from the perspective of Earth. Kepler-11 is the first discovered exoplanetary system with more than three transiting planets.
Kepler-11 is named for the Kepler Mission: it is the 11th star with confirmed planets discovered in the Kepler field of view. The planets are named alphabetically, starting with the innermost: b, c, d, e, f, and g, distinguishers that are tagged onto the name of their home star.
Kepler-11 is a G-type star that is approximately 96% the mass of and 107% the radius of the Sun. It has a surface temperature of about 5663 K and is estimated to have an age of around 8.5 billion years. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 13.7. Therefore, it cannot be seen with the naked eye.
All known planets transit the star; this means that all six planets' orbits appear to cross in front of their star as viewed from the Earth's perspective. Their inclinations relative to Earth's line of sight, or how far above or below the plane of sight they are, vary by a little more than a degree. This allows direct measurements of the planets' periods and relative diameters (compared to the host star) by monitoring each planet's transit of the star. Simulations suggest that the mean mutual inclinations of the planetary orbits are about 1°, meaning the system is probably more coplanar (flatter) than the Solar System, where the corresponding figure is 2.3°.
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