Gliese 581

Gliese 581 is a star, a Naine red located in the constellation of the Balance. Located at 20,5 light-years of the Solar system, it was in May 2007 about the 87e nearer known star.

Currently (May 2007), at least two Exoplanète S were detected around Gliese 581, of which one, Gliese 581 C, is the first exoplanète of low mass has to be found in the livable Zone of its star.

Star

Gliese 581 is a Naine red of spectral Type M2.5V. This type of star has a mass definitely lower than that of the Sun (a third in the case of Gliese 581), causing a rate of fusion of sound weaker Hydrogène inside its core. Consequently, the total luminosity of Gliese 581 is only 1,3% that of the Sun.

Gliese 581 is a variable star of the type BY Draconis, i.e. a star whose luminosity fluctuates because of variations of that of its Photosphère, combined with the axial rotation of star. Gliese 581 undergoes long-term changes of its luminosity, about a half magnitude. In the short run, it varies with more than 0,006 magnitude || orbital Period (D) || Equatorial radius (ua) || Eccentricity |- | align=" left" | Gliese 581 B || 15,6 || 5,366 || 0,041 || 0,02 ± 0,01 |- | align=" left" | Gliese 581 C || 5,1 || 12,91 || 0,073 || 0,16 ± 0,07 |- | align=" left" | Gliese 581 D || 7,6 || 83,6 ± 0,7 || 0,25 || 0,20 ± 0,10 |}

Gliese 581 B

Gliese 581 B is a planet of mass comparable with Neptune (15 times mass of the Earth) and evolving/moving around star in 5,4 days. This team, already responsible for discovered for Gliese 581 B in 2005, gathers Swiss, French and Portuguese astronomers. She used for this discovery the Spectrographe HARPS installed on the telescope of 3.6-m of the southern European Observatoire (ESO) with Silla (Chile).

Gliese 581 D

Gliese 581 would have a third planet, Gliese 581 D, of 8 times the mass of the Earth and turning around star in 84 days.

See too

Internal bonds

List of stars close
Dwarf List to exoplanètes
red

External bonds

GLIESE581@Home

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