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Kepler-14b is an extrasolar planet in orbit around the primary star of the binary Kepler-14 system. It is currently the only planet known to exist in this star system. Kepler-14b is 8.4 times the mass of Jupiter and has a radius 1.14 times that of Jupiter, and it orbits its host star every 6.79 days.〔 It was discovered by NASA-led Kepler mission, which noted the planet as a planetary candidate as early as March 2009, around the same time as the discovery of the first five planets discovered by Kepler (Kepler-4b to Kepler-8b). However, the team was unable to confirm the planet until extensive follow-up observations, as high-resolution imaging resolved the star Kepler-14 as a closely orbiting binary system. The Kepler team would have not noticed that Kepler-14 was a binary star based solely on initial radial velocity measurements (a standard method for confirming a planet's existence), and found that if they had not realized this, their data on Kepler-14b would have been very inaccurate. ==Discovery== NASA's Kepler spacecraft, which was launched in March 2009, collected photometric data continuously over a four-month period in a small area of sky, using a 0.95m Schmidt telescope. When the data collected during this period was analyzed, 1235 planetary candidates were identified amongst the observed 150,000 stars; all of these planetary candidates were suspected of transiting their host stars, in which the planetary body periodically crosses in front of and slightly dims its host star. Because the data collected on the transits of KOI-98 (later known as Kepler-14b) seemed very clearly to indicate a planet, Kepler identified KOI-98 early on in its mission. Data on the object of interest was forwarded to the Kepler Follow-up Program for a follow-up investigation.〔 The Fibre-fed Échelle Spectrograph (FIES) on the Canary Islands' Nordic Optical Telescope was operated in October 2009, using Doppler spectroscopy to gather information that would accompany the gathered photometric observations. The High Resolution Échelle Spectrometer (HIRES) at the W.M. Keck Observatory was also utilized. Use of the WIYN Observatory for speckle imaging found that the host star of KOI-98 was actually a close-knit binary star, which complicated the analysis. A November 2009 operation of the ARIES instrument on the MMT Observatory and the July 2010 use of the PHARO near-infrared camera on the Palomar Observatory's 200 inch Hale telescope used adaptive optics to confirm WIYN's findings. Although suspected as a planet early on, KOI-98 was not included when Kepler-4b, Kepler-5b, Kepler-6b, Kepler-7b, and Kepler-8b were published, as further investigation was still required.〔 Scientists investigated the possibility that the transit signal detected by Kepler was actually due to a third star in the system that eclipsed its sister stars. However a bisector analysis of the spectra of KOI-98's star ruled out that hypothesis.〔 On August 7, 2010, the Infrared Array Camera aboard the Spitzer Space Telescope was used to find the centroid, the point in space around which both of the Kepler-14 stars orbit. Analysis of the collected data determined which component of the binary star system was the site of the transit signal, and, additionally, that the transit signal came from the primary star in the system (as opposed to the fainter, less prominent star).〔 Using the spectral data collected by HIRES and FIES, the Kepler team derived the characteristics of the host star. The HIRES and FIES results agreed on every aspect of the star that had been derived except for the star's radial velocity. With the stellar parameters known, the Kepler team interpreted the Spitzer data to confirm that Kepler-14b was indeed a planet.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Kepler-14b」の詳細全文を読む スポンサード リンク
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