Kepler-89 is a star with four confirmed planets. Kepler-89 is a possible wide binary star.
Planetary system
The discovery of four planets orbiting the star was announced October 2012 by analyzing data gathered by
Kepler space telescope
The Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized Exoplanet, planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocen ...
.
Follow-up radial velocity measurements confirmed the existence of
Kepler-89d, indicating that Kepler-89d is slightly larger and more massive than
Saturn.
In October 2013, other three planets were confirmed with
Kepler-89c and
Kepler-89e getting reasonable mass constraints. Transit-timing variations of the outermost planet suggest that additional planets or minor bodies are present in the system.
In 2012, a partial transit of the second outermost planet by the outermost planet was reported. This was the first time a planet-planet transit in front of the star was detected.
This allowed to determine the mutual inclination of the planets d and e to be 1.15°.
Stephen R. Kane
Stephen Kane is a full professor of astronomy and planetary astrophysics at the University of California, Riverside who specializes in exoplanetary science. His work covers a broad range of exoplanet detection methods, including the microlensi ...
did a dynamical analysis of the Kepler-89 system that demonstrated that planets c and d, although close to the 2:1 secular
resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied Periodic function, periodic force (or a Fourier analysis, Fourier component of it) is equal or close to a natural frequency of the system ...
, are not permanently in a 2:1 resonance configuration.
References
{{2012 in space
Planetary systems with four confirmed planets
94
Cygnus (constellation)
F-type main-sequence stars
J19491993+4153280
Planetary transit variables