Detecting cold stars never seen

A weak, lonely and dim star, the lowest temperature ever recorded in history has been discovered, only 40 light-years from Earth.

This brown dwarf has a mass of about 15 to 30 times Jupiter and has a surface temperature of only 350 degrees Celsius - equal to the surface temperature at Mercury's equator and much colder than the surface of Venus - two planets in our solar system.

This object is particularly noticeable because it lies between the boundary of distinguishing large planets from tiny stars. Stars of this type are theoretically classified as a completely new star group - known as Y dwarfs. "This is the latest form of the spectrum between stars and planets, " said lead researcher Loic Albert from Canadian France Observatory in Hawaii said.

Because of the lack of light, Y dwarfs are difficult to find and identify. In fact no one has succeeded in identifying such a celestial body.

New faint star found.(Photo: Discovery)

"In the human eye, it is invisible, even in a telescope," Albert said. That's because it's not hot enough to glow red, and only emits infrared light. Therefore, the team must use infrared and near-infrared devices to find this dwarf Y. The key to discovering it is the presence of ammonia in the atmosphere.

Two types of previously classified brown dwarfs, L and T dwarfs, have obvious differences. L dwarfs are much hotter, reaching 1,200 - 2,000 degrees Celsius, and T dwarfs are colder, about 1,200 degrees Celsius and rich in methane.