FL Lyrae is the

variable star designation In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constell ...

for an

eclipsing binary A binary star is a system of two stars that are 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 using a telescope as separate stars, in wh ...

star system in the northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

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 ...

. The combined

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 ...

of the pair is 9.36, which means they are too faint to be seen with the naked eye.

Parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements put the system at a distance of around 437

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 from the Sun. This star system was in the view field of the

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 ...

space telescope during 2009−2014, which allowed monitoring during that spacecraft's mission. The variability of this system was discovered from photographic plates in 1935. It is a binary star system with an orbital plane that is nearly aligned with the line of sight to the

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 ...

. Once every 2.1781542 day orbit, each of the closely orbiting stars eclipses its partner, causing a net magnitude drop to 9.4 during the primary eclipse and to magnitude 9.1 when the secondary component is eclipsed. The secondary member covers 51% of the larger star during the primary eclipse, while the primary covers 88% of the secondary. The measureable properties of an eclipsing binary can allow the physical parameters of the individual components to be worked out in some detail. The primary component has 122% of the Sun's mass, spans 128% of the

radius of the Sun Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: :1\,R_ = 6.957\t ...

, and is emitting 217% of the Sun's luminosity. It is most likely an F-type main sequence star with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of F8. The secondary is smaller, with 96% of the mass of the Sun, 96% of the Sun's radius, and radiates just 65% of the Sun's luminosity. This is a G-type main sequence star of class G8. Based upon light variations measured during eclipses by the Kepler spacecraft, the system may contain a third body with twice the mass of Jupiter and an orbital period of under seven years. As of 2015, this remains to be confirmed.

References

{{Stars of Lyra G-type main-sequence stars F-type main-sequence stars Algol variables Lyra Durchmusterung objects 179890 094335 Lyrae, FL Kepler Input Catalog