Kepler-14b
A massive exoplanet in a binary star system discovered by Kepler.
Kepler-14b is an extrasolar planet orbiting the primary star of the binary Kepler-14 system. It is the only planet known in that system. The planet is notable for being discovered by the Kepler mission and for the complications arising from the fact that its host star is a close binary system, which initially made confirmation difficult and would have led to highly inaccurate planetary parameters if unrecognized.
Quick Facts
- Discoverer
- L. Buchhave et al.
- Discovery Site
- Kepler spacecraft
- Discovered
- Paper submitted 27 June 2011
- Discovery Method
- Transit method
- Apsis
- astron
- Eccentricity
- 0.035 (± 0.02)
- Inclination
- 90.0 0.0 · 2.8
- Star
- Kepler-14A (KOI-98)
- Density
- 7.1 (± 1.1) g cm / −3
Facts from the source article.
Lore & Background
Kepler-14b was identified as a planetary candidate (KOI-98) early in the Kepler mission, around the time the first five Kepler planets were announced. However, confirmation was delayed because high-resolution imaging revealed that the host star Kepler-14 is actually a close binary system. The Fibre-fed Échelle Spectrograph on the Nordic Optical Telescope and the High Resolution Échelle Spectrometer at the W.M. Keck Observatory were used for Doppler spectroscopy. Speckle imaging at the WIYN Observatory first indicated the binary nature, later confirmed by adaptive optics at the MMT Observatory and the Palomar Observatory. A bisector analysis ruled out the possibility that the transit signal came from a third star. The Spitzer Space Telescope's Infrared Array Camera determined the centroid of the binary system and identified the primary star as the source of the transit signal. The planet orbits the primary star (Kepler-14A) every 6.79 days at a mean distance about 8.213 times the star's radius. Its mass is 8.4 times that of Jupiter, and its radius is 1.136 times Jupiter's, giving a high density of 7.1 g/cm³. The orbital eccentricity is 0.035.
Reader's Guide
Kepler-14b's discovery highlights the importance of high-resolution imaging in exoplanet confirmation. The Kepler team noted that if the binary nature of Kepler-14 had not been detected, the derived mass of Kepler-14b would have been incorrect by nearly 60%, and its radius too small by about 10%. This underscores a potential systematic error in radial-velocity-based planet confirmations where unresolved binary stars may skew results. The planet itself is a massive, dense world orbiting very close to its host star, completing a revolution in under seven days. Its host system, a binary with an orbital period of roughly 2,800 years, is located about 980 parsecs away. The discovery process involved multiple observatories and instruments, from the Kepler spacecraft's photometry to ground-based spectroscopy and space-based centroid analysis. Kepler-14b remains the only known planet in its system, and its confirmation required careful disentangling of the binary star's light.
Did You Know?
- Kepler-14b is 8.4 times the mass of Jupiter but only 1.136 times its radius, giving it a high density of 7.1 g/cm³.
- The host star Kepler-14 is a binary system with an orbital period of about 2,800 years.
- If the binary nature had not been discovered, the planet's mass would have been off by nearly 60% and its radius too small by about 10%.
- The Spitzer Space Telescope was used to determine which star in the binary system the planet transits.
Frequently Asked Questions
What is Kepler-14b?
Kepler-14b is a gas-giant exoplanet that circles the primary star of the Kepler-14 binary system. It is the only confirmed planet in that system and was identified during the Kepler space telescope's transit survey.
How was Kepler-14b discovered and confirmed?
The Kepler mission first flagged a periodic dip in brightness, but the host turned out to be a close binary pair rather than a single star. Astronomers had to disentangle the blended light from both stars before they could verify the signal truly came from a transiting planet.
Why was confirming Kepler-14b so difficult?
The tight binary's combined light curve produced signatures that could mimic or distort a transit signal, making the initial confirmation ambiguous. Had the binary nature gone unnoticed, the derived mass, radius, and other orbital parameters would have been substantially off.
What are Kepler-14b's key physical characteristics?
The planet has a mass of roughly 8.4 Jupiter masses and a radius about 1.14 times Jupiter's, yielding a density near 7.1 g/cm³. It completes an orbit every 6.79 days around an F-type star, following a mildly elliptical path with an eccentricity of 0.035.
Why is Kepler-14b important to exoplanet science?
It stands as a cautionary example of how an undiscovered binary companion can silently corrupt every derived planetary parameter. Its confirmation reinforced the lesson that thorough stellar characterization is essential before any Kepler transit candidate is declared a true exoplanet.
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