Found closest to the Sun, a brown dwarf

08.04.2010

Astronomers have discovered the closest to the Earth brown dwarf. Article scientists accepted for publication in the journal Nature, and its preprint available at arXiv.org.



Brown dwarf. Figure NASA
 

 

The object was found in the program UKIDSS and is located at a distance of only 9 light years from our solar system, called UGPSJ0722-05. Since direct observation of brown dwarfs is a daunting task to determine the physical characteristics of the body, scientists have turned to computer simulation.

As a result, it was found that the weight of the object lying in the range from 5 to 30 Jupiter, and the radius is from 0.09 to 0.12 sun. For UGPSJ0722-05 is characterized by a low luminosity, indicating a very low temperature. Calculations show that it is 400-500 degrees Kelvin — it makes the dwarf one of the candidates to be the coldest brown dwarf known so far (this is now the object SDSS1416 +13 B, a temperature just below 500 degrees Kelvin).

In addition to the physical characteristics of dwarf researchers were able to obtain data on its chemical composition. So, it turned out that in the atmosphere of this object is present methane and water. Astrophysics also found that the atmosphere of the dwarf absorbs electromagnetic radiation with a wavelength of 1.25 micrometers. The researchers suggest that all of these facts point to UGPSJ0722-05 belongs to a completely new kind of celestial bodies.

Brown dwarfs are objects whose mass is between 13 and 80 Jupiter. These bodies are formed in the same scenario as the star — as a result of compression of gas clouds under the influence of its own gravity. However, the weight of dwarfs is not large enough in them to run the fusion reaction of hydrogen into helium, which feeds the usual stars.

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