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NN Serpentis (abbreviated NN Ser) is an eclipsing post-common envelope binary system approximately 1670
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
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 (constellation)
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 away. The system comprises an eclipsing white dwarf
A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...
and 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 ...
. 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.
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 standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of ...
.
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 mass more than two and a half times that of all the other planets in the Solar System combined, but ...
masses and orbital period of 7.56 years for this planet, probably located at 3.29 Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits t ...
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.
See also
*Algol
ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by the ...
* HW Virginis
HW Virginis, abbreviated HW Vir, is an eclipsing binary system (of the Algol type), approximately 563 light-years away based on the parallax measured by the Gaia spacecraft, in the constellation of Virgo. The system comprises an ecl ...
* CM Draconis
CM Draconis (GJ 630.1A) is an eclipsing binary system approximately 47 light-years away in the constellation of Draco (the Dragon). The system consists of two nearly identical red dwarf stars located in the constellation Draco. The two ...
* Kepler-16
Kepler-16 is an eclipsing binary star system in the constellation of Cygnus that was targeted by the Kepler spacecraft. Both stars are smaller than the Sun; the primary, Kepler-16A, is a K-type main-sequence star and the secondary, ...
* Kepler-47
Kepler-47 is a binary star system in the constellation Cygnus located about 1055 parsecs (3,442 light years) away from Earth. The stars have three exoplanets, all of which orbit both stars at the same time, making this a circumbinary sy ...
, another binary system with 3 planets
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 (constellation)