Kepler-13 or KOI-13 is a stellar triple star system consisting of Kepler-13A, around which an orbiting hot Jupiter

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

was discovered with the

Kepler spacecraft The Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orb ...

in 2011, and Kepler-13B a common

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

companion star which has an additional star orbiting it.

Stellar system

The multiple nature of the system was discovered in 1904 by Robert Grant Aitken at

Lick Observatory The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The observatory is managed by th ...

. He measured a separation between the A and B components of approximately one arc second and position angle of 281.3° with the 36" James Lick telescope. The position of the two visual components of the system relative to each other has remained constant since 1904.

Radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

measurements taken with the SOPHIE échelle spectrograph at the

Haute-Provence Observatory The Haute-Provence Observatory (OHP, french: Observatoire de Haute-Provence) is an astronomical observatory in the southeast of France, about 90 km east of Avignon and 100 km north of Marseille. It was established in 1937 as a national ...

revealed an additional companion orbiting Kepler-13B. This companion has a mass of between 0.4 and 1 times that of the Sun and orbits with a period of 65.831 days with an eccentricity of 0.52

Planetary system

Kepler-13 was identified as one of 1235 planetary candidates with transit-like signatures in the first four months of Kepler data. It was confirmed as a planet by measuring the

Doppler beaming Relativistic beaming (also known as Doppler beaming, Doppler boosting, or the headlight effect) is the process by which relativistic effects modify the apparent luminosity of emitting matter that is moving at speeds close to the speed of lig ...

effect on the Kepler light curve. The planet that has been confirmed, having a radius of between , is also one of the largest known exoplanets. The planet is likely to be tidally locked to the parent star. In 2015, the planetary nightside temperature was estimated to be equal to 2394 K.A Comprehensive Study of Kepler Phase Curves and Secondary Eclipses:Temperatures and Albedos of Confirmed Kepler Giant Planets
/ref> The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is mildly misaligned with the equatorial plane of the star, misalignment equal to 24°. The planetary transits are changing in duration over time which is likely caused by the interaction of the planet with its host star.

References

{{Sky, 19, 07, 33.107, +, 46, 52, 5.95 Planetary systems with one confirmed planet Planetary transit variables 13 J19075308+4652061 Lyra (constellation) Durchmusterung objects