NN Serpentis (abbreviated NN Ser) is an eclipsing post-common envelope binary system approximately 1670

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s away. The system comprises an eclipsing

white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...

and

red dwarf A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs are ...

. The two stars orbit each other every 0.13 days.

Planetary system

A planetary system has been inferred to exist around NN Ser by several teams. All of these teams rely on the fact that Earth sits in the same plane as the NN Serpentis binary star system, so humans can see the larger red dwarf eclipse the white dwarf every 0.13 days. Astronomers are then able to use these frequent eclipses to spot a pattern of small but significant irregularities in the orbit of stars, which could be attributed to the presence and gravitational influence of circumbinary planets. NNSerLightCurve

Chen (2009) used these "eclipse timing variations" to suggesting a putative orbital period spanning between 30 and 285 years and a minimum mass between 0.0043 and 0.18

Solar masses The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies ...

. In late 2009, Qian estimated a minimum mass of 10.7

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 ...

masses and orbital period of 7.56 years for this planet, probably located at 3.29

Astronomical Unit The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its m ...

s. This has since been disproven by further measurements of the eclipse times of the binary stars. In late 2009 and 2010, researchers from the UK (University of Warwick and the University of Sheffield), Germany (Georg-August-Universitat in Göttingen, Eberhard-Karls-Universitat in Tübingen), Chile (Universidad de Valparaíso), and the United States (University of Texas at Austin) suggested that the eclipse timing variations are caused by two gas giant planets. The more massive gas giant is about 6 times the mass of Jupiter and orbits the binary star every 15.5 years, the other orbits every 7.75 years and is about 1.6 times the mass of Jupiter. All published planetary models have failed to predict changes in eclipse timing since 2018, suggesting that a different explanation for the eclipse timing variations may be needed.

References

External links

The Extrasolar Planet Encyclopaedia — Catalog Listing

UK Astronomers Help Find Snooker Star System
{{DEFAULTSORT:NN Serpentis Eclipsing binaries Serpentis, NN White dwarfs M-type main-sequence stars 2 Hypothetical planetary systems Serpens

Planetary system

See also

References

External links