Gliese 581 is an M-class red dwarf star that is not far from the Earth. It is 22 light years away from the Solar system. This makes it the 89th closest known star to the Sun. It is also known as HO Librae, GL 581, or GJ 581.
Astronomers have discovered some planets that orbit Gliese 581. The astronomers agree that four of the planets are real, but some think there are two more planets.
Gliese 581 has a radius, and mass, about a third that of the Sun. Its estimated temperature is 3,498 Kelvin (4125 Celsius, 7457 Fahrenheit). Its luminosity is 0.01205 times the luminosity of the Sun.
People on Earth can see Gliese 581 in the constellation Libra. The star's apparent magnitude is 10.57. This means that a person on Earth would need to use a telescope to see Gliese 581, because the star is not bright enough for the naked eye to see.