Kepler-14b
Encyclopedia
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.
'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.
s (3,196 light years) from Earth.
Kepler-14b's host star is the primary (A) component of the Kepler-14 binary system. However, because the binary system is so closely knit, it was impossible at the time of Kepler-14b's discovery to distinguish the characteristics of each individual star. If the Kepler-14 system was an individual star, it would be an F-type star. With an apparent magnitude
of 12.12, the star system is not visible from Earth with the naked eye. Kepler-14's combined results resemble that of a star that is 1.512 solar mass
es and 2.048 solar radii. Its gyrochronological age
, or its age as determined by the rate at which a star spins, is estimated at 2.2 billion years, far younger than the Sun. It is also hotter, with an effective temperature
of 6395 K. With a metallicity
of 0.12, Kepler-14 has 132% more iron than the amount measured in the Sun.
es and 1.136 Jupiter radii. In other words, the planet is 8.4 times more massive than Jupiter, but only 1.136 times Jupiter's size. This equates to a high density, which is measured at 7.1 g cm−3. According to the Extrasolar Planets Encyclopaedia
, which calculated Kepler-14b's eccentricity independently, Kepler-14b has a slightly irregular orbit, with an orbital eccentricity
of 0.035. Kepler-14b takes approximately 6.79 days to orbit
its host star. The mean distance from its host star is about 8.213 times the measured radius of Kepler-14.
The authors of Kepler-14b's discovery paper noted that, had they not discovered that Kepler-14 was indeed a binary system, the parameters for Kepler-14b would have been extremely inaccurate. They noted that other planets discovered using radial velocity measurements might not have accounted for the possibility that their host stars were binary systems; the only way that this was definitely known in the case of Kepler-14 was through the use of high-resolution imaging. If the less prominent portion of the Kepler-14 binary system had not been detected, Kepler-14b's mass would have been incorrect by nearly 60%, and its radius too small by about 10%.
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
Kepler-14
Kepler-14
Kepler-14 is a binary star system targeted by the Kepler spacecraft. It is host to one known planet: the Jupiter-like Kepler-14b. The star system was identified early by Kepler as a possible planetary host, but when imaging revealed that Kepler-14 was a binary star system and not a single star, the...
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
Kepler-4b
Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System. The planet's...
to Kepler-8b
Kepler-8b
Kepler-8b is the fifth of the first five exoplanets discovered by NASA's Kepler spacecraft, which aims to discover planets in a region of the sky between the constellations Lyra and Cygnus that transit their host stars. The planet is the hottest of the five...
). 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
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic 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
NASANASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Kepler spacecraft, which was launched in March 2009, collected photometric
Photometry (astronomy)
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...
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
Kepler Object of Interest
A Kepler Object of Interest is a star observed by the Kepler spacecraft which is suspected of hosting one or more transiting planets. KOIs come from a master list of 150,000 stars which itself is generated from the Kepler Input Catalog . A KOI shows a periodic dimming, indicative of an unseen...
-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
Kepler Follow-up Program
The Kepler-Follow-up Program, known also as the Kepler Follow-up Observation Program and KFOP, is a program instituted to conduct follow-up observations on Kepler Objects of Interest , or signals noticed by the Kepler spacecraft that may indicate the presence of a planet transiting its host star...
for a follow-up investigation.
The Fibre-fed Échelle Spectrograph (FIES) on the Canary Islands' Nordic Optical Telescope
Nordic Optical Telescope
The Nordic Optical Telescope is an astronomical telescope located at Roque de los Muchachos Observatory, La Palma in the Canary Islands. First light came in 1988, with regular observing beginning in 1989. It is funded by Denmark, Sweden, Iceland, Norway and Finland...
was operated in October 2009, using Doppler spectroscopy
Doppler spectroscopy
Doppler spectroscopy, also known as radial velocity measurement, is a spectroscopic method for finding extrasolar planets. It involves the observation of Doppler shifts in the spectrum of the star around which the planet orbits....
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
WIYN Observatory
The WIYN Observatory is owned and operated by the WIYN Consortium. Its telescope, a 3.5-meter instrument, is the newest and second largest telescope on Kitt Peak in Arizona...
for speckle imaging
Speckle imaging
Speckle imaging describes a range of high-resolution astronomical imaging techniques based either on the shift-and-add method or on speckle interferometry methods...
found that the host star of KOI-98 was actually a close-knit binary star
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
, which complicated the analysis. A November 2009 operation of the ARIES instrument on the MMT Observatory
MMT Observatory
The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains...
and the July 2010 use of the PHARO near-infrared camera on the Palomar Observatory
Palomar Observatory
Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...
's 200 inch Hale telescope
Hale telescope
The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning...
used adaptive optics
Adaptive optics
Adaptive optics is a technology used to improve the performance of optical systems by reducing the effect of wavefront distortions. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, and in retinal imaging systems to reduce the...
to confirm WIYN's findings. Although suspected as a planet early on, KOI-98 was not included when Kepler-4b
Kepler-4b
Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System. The planet's...
, Kepler-5b
Kepler-5b
Kepler-5b is one of the first five planets discovered by NASA's Kepler spacecraft. It is a Hot Jupiter that orbits a subgiant star that is more massive, larger, and more diffuse than the Sun is...
, Kepler-6b
Kepler-6b
Kepler-6b is an extrasolar planet in the orbit of the unusually metal-rich Kepler-6, a star in the field of view of the NASA-operated Kepler spacecraft, which searches for planets that cross directly in front of, or transit, their host stars. It was the third planet to be discovered by Kepler....
, Kepler-7b
Kepler-7b
Kepler-7b is one of the first five planets to be confirmed by NASA's Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It is in the orbit of a star that is not as hot as the Sun, but is significantly larger and is expected to soon reach the end of the main...
, and Kepler-8b
Kepler-8b
Kepler-8b is the fifth of the first five exoplanets discovered by NASA's Kepler spacecraft, which aims to discover planets in a region of the sky between the constellations Lyra and Cygnus that transit their host stars. The planet is the hottest of the five...
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
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
of KOI-98's star ruled out that hypothesis.
On August 7, 2010, the Infrared Array Camera aboard the Spitzer Space Telescope
Spitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...
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
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...
. With the stellar parameters known, the Kepler team interpreted the Spitzer data to confirm that Kepler-14b was indeed a planet.
Host star system
Kepler-14 is a binary star system, which means that it is actually composed of two gravitationally bound stars that orbit a common point in space. The system is composed of a primary star, Kepler-14A, and a dimmer companion star, Kepler-14B. When the stars were observed, while searching for the planet Kepler-14b, the angular separation of the binary system made it extremely difficult to note the dimmer companion star. The stars have such a wide orbit that it takes approximately 2800 years for each star to complete a revolution around the centroid. The two stars are located approximately 980 parsecParsec
The parsec is a unit of length used in astronomy. It is about 3.26 light-years, or just under 31 trillion kilometres ....
s (3,196 light years) from Earth.
Kepler-14b's host star is the primary (A) component of the Kepler-14 binary system. However, because the binary system is so closely knit, it was impossible at the time of Kepler-14b's discovery to distinguish the characteristics of each individual star. If the Kepler-14 system was an individual star, it would be an F-type star. With an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 12.12, the star system is not visible from Earth with the naked eye. Kepler-14's combined results resemble that of a star that is 1.512 solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
es and 2.048 solar radii. Its gyrochronological age
Gyrochronological age
The gyrochronological age of a star is determined by using the rate at which the star spins to find its true age. The process of the star was presented by Søren Meibom, who used data collected by the Kepler spacecraft to present his findings in 2010 after he analyzed cluster NGC 6811....
, or its age as determined by the rate at which a star spins, is estimated at 2.2 billion years, far younger than the Sun. It is also hotter, with an effective temperature
Effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation...
of 6395 K. With a metallicity
Metallicity
In astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...
of 0.12, Kepler-14 has 132% more iron than the amount measured in the Sun.
Characteristics
Kepler-14b is the sole planet discovered in the Kepler-14 system to date. The planet orbits the primary star in the Kepler-14 binary system. Kepler-14b is estimated to have 8.40 Jupiter massJupiter mass
Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....
es and 1.136 Jupiter radii. In other words, the planet is 8.4 times more massive than Jupiter, but only 1.136 times Jupiter's size. This equates to a high density, which is measured at 7.1 g cm−3. According to the Extrasolar Planets Encyclopaedia
Extrasolar Planets Encyclopaedia
The Extrasolar Planets Encyclopedia is an astronomy website, founded in Paris, France at the Meudon Observatory by Jean Schneider in February 1995, which maintains a database of all the currently known and candidate extrasolar planets, with individual "note" pages for each planet and a full list...
, which calculated Kepler-14b's eccentricity independently, Kepler-14b has a slightly irregular orbit, with an orbital eccentricity
Orbital eccentricity
The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
of 0.035. Kepler-14b takes approximately 6.79 days to orbit
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...
its host star. The mean distance from its host star is about 8.213 times the measured radius of Kepler-14.
The authors of Kepler-14b's discovery paper noted that, had they not discovered that Kepler-14 was indeed a binary system, the parameters for Kepler-14b would have been extremely inaccurate. They noted that other planets discovered using radial velocity measurements might not have accounted for the possibility that their host stars were binary systems; the only way that this was definitely known in the case of Kepler-14 was through the use of high-resolution imaging. If the less prominent portion of the Kepler-14 binary system had not been detected, Kepler-14b's mass would have been incorrect by nearly 60%, and its radius too small by about 10%.