Kepler-419c (also known by its Kepler Object of Interest designation ''KOI-1474.02'') is a

super-Jupiter A super-Jupiter is a gas giant exoplanet that is more massive than the planet Jupiter. For example, companions at the planet–brown dwarf borderline have been called super-Jupiters, such as around the star Kappa Andromedae. By 2011 there were ...

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 ...

orbiting within the

habitable zone In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.J. F. Kas ...

of the star

Kepler-419 Kepler-419 is an F-type main-sequence star located about 3,400 light years from Earth in the constellation Cygnus. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect ...

, the outermost of two such planets discovered by

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, succeeding t ...

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 ...

. It is located about 3,400

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s (1040

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

s )from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

in the constellation Cygnus. The exoplanet was found by using the transit timing variation method, in which the variations of transit data from an exoplanet are studied to reveal a more distant companion.

Physical characteristics

Mass, radius and temperature

Kepler-419c is a

, an exoplanet that has a radius and mass greater than that of the planet

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

. It has a temperature of , somewhat cooler than the

equilibrium temperature The planetary equilibrium temperature is a theoretical temperature that a planet would be if it were a black body being heated only by its parent star. In this model, the presence or absence of an atmosphere (and therefore any greenhouse effect) is ...

of the Earth.http://www.hpcf.upr.edu/~abel/phl/hec_plots/hec_orbit/hec_orbit_Kepler-419_c.png It has a mass of 7.2 , and a likely radius of around 1.13 , based on its high mass.

Host star

The planet orbits an ( F-type)

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

named

. The star has a mass of 1.39 and a radius of 1.75 . It has a surface temperature of 6430 K and is 2.8 billion years old. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K. The star's

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

, or how bright it appears from Earth's perspective, is 12. It is too dim to be seen with the naked eye.

Orbit

Kepler-419c orbits its host star with 270% of the Sun's luminosity (2.7 ) about every 675 days (around 1.84 years) at a distance of 1.61 AU (compared to the orbital distance of

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

, which is 1.52 AU). It has a slightly eccentric orbit, with an eccentricity of 0.184. It receives about 95% of the amount of

sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...

that Earth does.

Habitability

Kepler-419c resides in the circumstellar

of the parent star. The exoplanet, with a mass of 7.28 , is too massive to be rocky, and because of this the planet itself may not be habitable. However, Kepler-419c is listed as one of the candidates that may harbor potentially habitable moons, where, with the right atmospheric pressure and temperature, liquid water might exist on the surface of the moon. Hypothetically, for a stable orbit the ratio between the moon's

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 ...

''P''_s around its primary and that of the primary around its star ''P''_p must be < 1/9, e.g. if a planet takes 90 days to orbit its star, the maximum stable orbit for a moon of that planet is less than 10 days. Simulations suggest that a moon with an orbital period less than about 45 to 60 days will remain safely bound to a massive giant planet or

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

that orbits 1 AU from a Sun-like star. In the case of Kepler-419c, this would be practically the same to have a stable orbit, albeit a bit longer, around 65 days.

Discovery

In 2009,

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 o ...

spacecraft was completing observing stars on its

photometer A photometer is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Most photometers convert light into an electric current using a photoresistor, ph ...

, the instrument it uses to detect

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 ...

events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In this last test, Kepler observed stars in the

Kepler Input Catalog The Kepler Input Catalog (or KIC) is a publicly searchable database of roughly 13.2 million targets used for the Kepler Spectral Classification Program (SCP) and ''Kepler''. Overview The Kepler SCP targets were observed by the 2MASS project ...

, including Kepler-419, the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up at observatories. Observations for the potential exoplanet candidates took place between 13 May 2009 and 17 March 2012. After observing the respective transits, the first planet,

Kepler-419b Kepler-419b (also known by its Kepler Object of Interest designation ''KOI-1474.01'') is a hot Jupiter exoplanet orbiting the star Kepler-419, the outermost of two such planets discovered by NASA's Kepler spacecraft. It is located about 3,400 lig ...

, was announced. Further investigations were made into the transit data of Kepler-419b, which was shown to be varying slightly, caused by a more distant orbiting planet. Data revealed that the responsible companion was about 7.3 times more massive than Jupiter and orbiting at a distance of 1.68 AU. The discovery was then announced on June 12, 2014.

References

The Extrasolar Planets Encyclopaedia The Extrasolar Planets Encyclopaedia 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 indi ...

. {{Sky, 19, 41, 40.3, +, 51, 11, 05.15 Exoplanets discovered by the Kepler space telescope Giant planets Exoplanets discovered in 2014 Transiting exoplanets Giant planets in the habitable zone Cygnus (constellation)