__NOTOC__ Kepler-6b is an

extrasolar planet 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 ...

in the orbit of the unusually metal-rich Kepler-6, a star in the field of view of the

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedi ...

-operated

Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of ...

spacecraft, which searches for planets that cross directly in front of, or

transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1979 film), a 1979 Israeli film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 ...

, their host stars. It was the third planet to be discovered by Kepler. Kepler-6 orbits its host star every three days from a distance of .046 AU. Its proximity to Kepler-6 inflated the planet, about two-thirds the mass of Jupiter, to slightly larger than Jupiter's size and greatly heated its atmosphere. Follow-up observations led to the planet's confirmation, which was announced at a meeting of the American Astronomical Society on January 4, 2010 along with four other Kepler-discovered planets.

Discovery and naming

's Kepler satellite trails the Earth and continually observes a portion of the sky between the constellations Cygnus and

Lyra Lyra (; Latin for lyre, from Greek ''λύρα'') is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra was ...

. It is devised to search for and discover planets that

, or cross in front of, their host stars with respect to Earth by measuring small and generally periodic variations in a star's brightness. Kepler recognized a potential transit event around a star that was designated KOI-017, which was named Kepler-6 after the confirmation of Kepler-6b. The star was designated "6" because it was the sixth planet to be observed (but the third planet to be discovered) by the Kepler satellite. After the initial detection of a transit signal by Kepler, follow-up observations were taken to confirm the planetary nature of the candidate.

Speckle imaging Speckle imaging describes a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add ("'' ...

by the

WIYN Telescope The WIYN Observatory is owned and operated by the WIYN Consortium. Its 3.5- meter telescope is the second largest optical telescope at Kitt Peak National Observatory in Arizona. Most of the capital costs for the observatory were provided by the ...

was used to determine the amount of light from nearby, background stars that was present. If not accounted for, this light would have made Kepler-6 appear brighter than it actually was. Consequently, the size of Kepler-6b would have been underestimated.

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 rate of change of the distance or range between the two points. It is equivalent to the vector projection ...

data was taken by HIRES at the

Keck I The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have aperture primary mirrors, and when com ...

telescope in order to determine the mass of the planet. Independently, observations were made with the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from aroun ...

wavelengths of 3.6 and 4.5 micrometres. Along with additional data taken by Kepler, these observations detected the

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

and phase curves of Kepler-6b behind its star. The confirmation of Kepler-6b was announced at the 215th meeting of the American Astronomical Society with the discoveries of planets Kepler-4b, Kepler-5b,

Kepler-7b Kepler-7b is one of the first five exoplanets to be confirmed by NASA's Kepler space telescope, Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It orbits a star slightly hotter and significantly larger ...

, and Kepler-8b on January 4, 2010.

Host star

Kepler-6 is a sunlike star in the Cygnus constellation. It is approximately 20.9% more massive than and 39.1% larger than the Sun. With an

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. Effective temperature is often used as an estimate of a body's surface temperature ...

of 5647 K, Kepler-6 is cooler than the Sun. It is predicted to be 3.8 billion years old, compared to the Sun's age of 4.6 billion years. It is most notable for its unusually high

metallicity In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as ...

for an exoplanet-bearing star; with an e/H= 0.34, Kepler-6 has 2.18 times more iron than the Sun does. Kepler-6b is the only planet that has been discovered in the orbit of Kepler-6.

Characteristics

Kepler-6b is a

hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital periods (). The close proximity to their stars and high surface-atmosphere temp ...

, having a mass 0.669 times that of Jupiter, but an

average distance In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the lon ...

of only 0.046 AU from its star and, thus, an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 3.23 days. It is almost 10 times closer to its star than Mercury is from our Sun. As a result, Kepler-6b is strongly irradiated by its star, heating its atmosphere to a temperature of 1660 K and puffing it up to a size 1.3 times that of Jupiter. It may also be the case that Kepler-6b has a

thermal inversion In meteorology, an inversion is a deviation from the normal change of an atmospheric property with altitude. It almost always refers to an inversion of the air temperature lapse rate, in which case it is called a temperature inversion. No ...

of its atmosphere, where temperature increases with increasing distance from the center of the planet. The planet is likely to be tidally locked to the parent star. In 2015, the planetary nightside temperature was estimated to be equal to 1719 K.A Comprehensive Study of Kepler Phase Curves and Secondary Eclipses:Temperatures and Albedos of Confirmed Kepler Giant Planets
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References

External links

{{Sky, 19, 47, 20.9, +, 48, 14, 23.8 Exoplanets discovered in 2010 Hot Jupiters Giant planets Transiting exoplanets Cygnus (constellation) 6b