Gliese 581

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Gliese 581 [ gli ː zə ] is about 20 light years ( 190 trillion km ) distant star in the constellation Libra. He is among the hundred closest to the Sun and stars is mostly associated with its catalog number 581 close to the Sun from the catalog star ( Catalogue of Nearby Stars, 1957) by Wilhelm Gliese called. There is a red dwarf of spectral type M2.5, which radiates about 500 times weaker than our Sun and has only a third of its mass. There are secured four planetary companions, another is very likely. Gliese 581 g has been suggested, but could not be confirmed.

Planet

Gliese 581 b

Gliese 581 b is about 17 times the mass of Earth and orbits its star every 5.366 days at a distance of six million kilometers. The exoplanet was discovered by a research team of astronomers from Switzerland, France and Portugal by Michel Mayor, Stéphane Udry and Xavier Delfosse 2005. It is similar in mass to Neptune ago. The short distance of this planet, however, has a surface temperature of 150 degrees Celsius and valued is more likely to consist of heavier elements (see below cosmochemistry ). So here are similar conditions on how the system Gliese 876

Gliese 581 c

This planet discovered in 2007 is one of the smallest known exoplanets. It has an estimated 1.5 times the diameter of Earth and about five times the mass of Earth. The orbital period or year length of Gliese 581 c is 13 days.

He is possibly still in the habitable zone of its solar system, ie in the area where water can exist permanently and in sufficient quantities in the liquid state due to the prevailing temperatures. However, recent research indicates that it is too close to its sun and thus it is too hot.

Gliese 581 d

The data on which Gliese 581 c was discovered, also strongly suggest a third planet with eight Earth masses and an orbital period of about 66 days. First, it was assumed, if he were on the outer edge of the habitable zone in theory, but had the track parameters are recalculated by the discovery of Gliese 581 e. The newly calculated orbit is slightly closer to the sun and thus in the middle of the habitable zone theory.

Gliese 581 e

With about 1.9 Earth masses, Gliese 581 e of the planet to date lightest ever found outside our solar system (as of August 2009). It orbits its star every 3.15 days and is to all appearances a rocky planet.

Gliese 581 f

Gliese 581 f has at least 7 times Earth's mass and orbits its star every 433 days.

Gliese 581 g

The publication of the possible discovery of Gliese 581 g was carried out jointly with Gliese 581 f on 27 September 2010. Was called, among other things as may erdähnlichster previously known exoplanets, and it was speculated that Gliese 581 g may consists of stone and have enough mass to hold an atmosphere. According to the published data path he would have been in the habitable zone.

An independent reanalysis of the data, published on 5 January 2011, indicates that Gliese 581 g also no longer exists. For this purpose, models were simulated for a theoretical model of a planet up to six planets. The analysis of the HARPS data shows that five planets are relatively safe to prove. The data for Gliese 581 b - e are plausible, the still uncertain for Gliese f. For a sixth planet no clue could be found. Thus, the HARPS data includes Gliese 581 g with the values ​​previously published.