Kepler-451 (also known as 2MASS J19383260+4603591 and abbreviated to 2M1938+4603) is an eclipsing post-common envelope binary

star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speak ...

that comprises two stars, a pulsating

subdwarf B star A B-type subdwarf (sdB) is a kind of subdwarf star with spectral type B. They differ from the typical subdwarf by being much hotter and brighter. They are situated at the "extreme horizontal branch" of the Hertzsprung–Russell diagram. Masses o ...

and a small

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

star. It is located about away in the constellation Cygnus. It has been hypothesized to host one or more

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 ...

Planetary system

Periodic variations in the timing of this system's eclipses were detected in 2015 using data from the

Kepler space telescope 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 was proposed that these variations are caused by the gravitational effects of a Jupiter-mass planet, Kepler-451b, orbiting with a period of 416 days at a distance of 0.92 AU. The existence of planets in this system is disputed. An independent study in 2020 found no evidence for Kepler-451b, ruling out the presence of any object of at least Jupiter's mass on the claimed orbit with an inclination greater than 43°. A 2022 study instead proposed a three-planet model, including the originally claimed planet as well as two other planets of similar mass with orbital periods of 43 and 1,800 days. In general, eclipse timing variations of this type are common in post-common envelope binary systems, and their true cause remains uncertain.

References

{{Cygnus (constellation) Binary stars M-type main-sequence stars B-type subdwarfs J19383260+4603591 Hypothetical planetary systems Cygnus (constellation)

451 __NOTOC__ Year 451 ( CDLI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Marcianus and Adelfius (or, less frequently, year 1204 '' ...