Gliese 581c

Gliese 581c
	Size comparison of Gliese 581c with Earth and Neptune ; (based on selected hypothetical modeled compositions)
Discovery
Discovered by	Stéphane Udry et al.
Discovery site	La Silla Observatory
Discovery date	4 April 2007; 24 April 2007 (announced);
Detection method	Radial velocity
Orbital characteristics
Semi-major axis	0.0718+0.0008; −0.0009 AU
Eccentricity	0.032+0.027; −0.021
Orbital period (sidereal)	12.9211+0.0008; −0.0007 d
Inclination	47°+15°; −13°
Time of periastron	2454759.2 ± 0.1
Argument of periastron	16°+61°; −89°
Semi-amplitude	3.1±0.1 m/s
Star	Gliese 581
Physical characteristics
Mass	6.81+0.21; −1.16 M🜨

Gliese 581c /ˈɡliːzə/ (Gl 581c or GJ 581c) is an exoplanet orbiting within the Gliese 581 system. It is the second planet discovered in the system and the third in order from the star. With a mass about 6.8 times that of the Earth, it is classified as a super-Earth (a category of planets with masses greater than Earth's up to ten Earth masses).

At the time of its discovery in 2007, Gliese 581c gained interest from astronomers because it was reported to be the first potentially Earth-like planet in the habitable zone of its star, with a temperature right for liquid water on its surface, and, by extension, potentially capable of supporting extremophile forms of Earth-like life. However, further research cast doubt upon the planet's habitability. Based on newer models of the habitable zone, the planet is likely too hot to be potentially habitable.^[4]^[3]

In astronomical terms, the Gliese 581 system is relatively close to Earth, at 20.55 light-years (194 trillion kilometres; 121 trillion miles) in the direction of the constellation of Libra. This distance, along with the declination and right ascension coordinates, give its exact location in the Milky Way.

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^ ^a ^b Cite error: The named reference vonStauffenberg2024 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference robertson2014 was invoked but never defined (see the help page).
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[robertson2014-4] Cite error: The named reference robertson2014 was invoked but never defined (see the help page).

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