Gliese 486, also known as Wolf 437 and formally named Gar, is a

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 ...

star away in the constellation

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. It hosts one known

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 ...

Nomenclature

The designation ''Gliese 486'' comes from the

Gliese Catalogue of Nearby Stars The ''Gliese Catalogue of Nearby Stars'' (, English ) is a star catalogue listing stars located within 25 parsecs (82 ly) of the Sun. First edition and supplements In 1957, German astronomer Wilhelm Gliese published his first star ca ...

. This was the 486th star listed in the first edition of the catalogue. In August 2022, this planetary system was included among 20 systems to be named by the third

NameExoWorlds NameExoWorlds (also known as IAU NameExoWorlds) were various projects managed by the International Astronomical Union (I.A.U.) to encourage names to be submitted for astronomical objects, notably exoplanets. The accepted names would later be cons ...

project. The approved names, proposed by a team from

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, were announced in June 2023. Gliese 486 is named Gar and its planet is named Su, after the

Basque Basque may refer to: * Basques, an ethnic group of Spain and France * Basque language, their language Places * Basque Country (greater region), the homeland of the Basque people with parts in both Spain and France * Basque Country (autonomous co ...

words for "flame" and "fire".

Properties

Gliese 486 has a surface temperature of 3340 K. Gliese 486 is similar to the Sun in its concentration of heavy elements, with a

metallicity In astronomy, metallicity is the Abundance of the chemical elements, abundance of Chemical element, elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-Dark matter, dark) matt ...

Fe/H index of 0.07. It was suspected to be a

flare star A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to magnetic reconnection, the magne ...

, although measurements available in 2019 did not reveal any flares. The chemical makeup of the star is unremarkable and consistent with solar abundances or being slightly metal-poor. The star has an unremarkable magnetic field in the chromosphere of about 1.6

kilogauss The gauss (symbol: , sometimes Gs) is a unit of measurement of magnetic induction, also known as magnetic flux density. The unit is part of the Gaussian system of units, which inherited it from the older centimetre–gram–second electromagne ...

. It is rotating very slowly and is likely to be very old, belonging kinematically to the old thin disk of the Milky Way. Multiplicity surveys did not detect any stellar companions to Gliese 486 as of 2020.

Planetary system

In 2021, one planet, named Gliese 486 b, was discovered on a tight, circular orbit. It represents a rare class of rocky exoplanet suitable for spectroscopic characterization in the near future by the

James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...

. By 2022, no hydrogen or steam dominated atmosphere was detected, although a secondary planetary atmosphere with a higher molecular weight remained a possibility. Observations by JWST announced in 2023 detected signs of

water vapor Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from th ...

, but it was unclear if this is from the planet's atmosphere or from its host star. Secondary eclipse observations by JWST published in 2024 show a planetary dayside temperature of (). This is consistent with a lack of heat redistribution, indicating that the planet likely has little to no atmosphere and the previous water vapor detection was likely a result of contamination from the host star. Gliese 486 b is thus similar to other hot rocky planets around red dwarfs, such as

LHS 3844 b LHS 3844 b, formally named Kua'kua, is an exoplanet orbiting the red dwarf LHS 3844, about away in the constellation Indus, discovered using the Transiting Exoplanet Survey Satellite. It orbits its parent star once every 11 hours, and its radiu ...

GJ 1252 b GJ 1252 is a red dwarf star located away from the Solar System in the constellation of Telescopium. The star has about 38% the mass and 39% the radius of the Sun, and a temperature of about . GJ 1252 is orbited by one known exoplanet. Pl ...

TRAPPIST-1b TRAPPIST-1b is a terrestrial, Earth-sized exoplanet orbiting around the ultra-cool dwarf star TRAPPIST-1, located away from Earth in the constellation of Aquarius. The planet was detected using the transit method, where a planet dims the host ...

, and GJ 1132 b.

References

{{DEFAULTSORT:Gliese 486 Virgo (constellation) Planetary transit variables M-type main-sequence stars Planetary systems with one confirmed planet J12475664+0945050 0486 062452 390651552

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Gar Gars are an ancient group of ray-finned fish in the family Lepisosteidae. They comprise seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine waters of eastern North America, Central America and Cuba ...

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