Kepler-1647b (sometimes named Kepler-1647(AB)b to distinguish it from the secondary component) is a circumbinary

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...

that orbits the

binary star system A binary star or binary star system is a Star system, system of two stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved ...

Kepler-1647, located from Earth in the constellation Cygnus. It was announced on June 13, 2016, in San Diego at a meeting of the American Astronomical Society. It was detected using the

transit method Methods of detecting exoplanets usually rely on indirect strategies – that is, they do not directly image the planet but deduce its existence from another signal. Any planet is an extremely faint light source compared to its parent star. For e ...

, when it caused the dimming of the primary star, and then again of the secondary star blended with the primary star eclipse. The first transit of the planet was identified in 2012, but at the time the single event was not enough to rule out contamination, or confirm it as a planet. It was discovered by the analysis of the Kepler

light-curve In astronomy, a light curve is a graph of the light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the ''y''-axis and with time on the ''x''-axis. The light is usually in a par ...

, which showed the planet in transit.

Characteristics

Mass and orbit

The exoplanet is a gas giant, similar in size to

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 Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

, and has an orbital period of 1107 days. This is the longest transit period of any confirmed transiting Kepler exoplanet discovered yet. It is also the largest circumbinary Kepler planet known. It is times more massive than Earth, and times Jupiter's mass.

Host stars

The star system, Kepler-1647 (also known as ''

2MASS The Two Micron All-Sky Survey, or 2MASS, was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and ...

J19523602+4039222'', ''

KOI , or more specifically , are colored varieties of carp ('' Cyprinus'' sp.) that are kept for decorative purposes in outdoor koi ponds or water gardens. Koi is an informal name for the colored variants of carp kept for ornamental purposes. ...

-2939'', and '' KIC 5473556,

TIC A tic is a sudden and repetitive motor movement or vocalization that is not rhythmic and involves discrete muscle groups. Tics are typically brief and may resemble a normal behavioral characteristic or gesture. Tics can be invisible to the obs ...

170344769'' ), is a binary star with the primary star (Kepler-1647 A) having a mass of 1.22 , a radius of 1.79 , and a surface temperature of 6210 ± 100 K. The secondary star (Kepler-1647 B), on the other hand, has a mass of 0.975 , a radius of 1.79 , and a surface temperature of 5770 K. In comparison, the Sun has a surface temperature of 5778 K. The two orbit each other every 11 days. The binary star system's age is estimated to be about 4.4 billion years old, about 200 million years younger than the Sun.

Habitability

Kepler-1647b is in the

habitable zone In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressu ...

of the star system. Since the planet is a gas giant, it is unlikely to host life. However, hypothetical large moons could potentially be suitable for life. Large moons are usually not created during

accretion Accretion may refer to: Science * Accretion (astrophysics), the formation of planets and other bodies by collection of material through gravity * Accretion (meteorology), the process by which water vapor in clouds forms water droplets around nucl ...

near a gas giant and would likely have to be captured separately, e.g., a passing

protoplanet A protoplanet is a large planetary embryo that originated within a protoplanetary disk and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitatio ...

caught into orbit due to the gravitational field of the giant planet. Given that the planet is within the habitable zone, its hypothetical moon would also be. The work showed that the system has the ability to house an Earth-like moon around the gas giant. With that, it would be able to house life as we know it.

References

External links