The multiple star system Sigma Orionis is visible in the sky with the naked eye. The black and white section shows SOri70, taken with the William Herschel telescope. (Image sources: University of Hawaii, Victor Bejar, Eduardo Martin)
Read An international team of astronomers photographed an object 1150 light-years away in the constellation of Orion, which could be a Jupiter-sized planet. However, it is strange that this object is 36, 000 times as far from the next star as Jupiter is from our sun. The researchers discuss their discovery at a symposium of the International Astronomical Union in Hawaii. What is certain is that SOri70 is an "ultracold" object. Ultra-cold in this context means that the temperature is at most 900 degrees Celsius. The researchers know that because they discovered the spectral lines of methane on the images of this object. It follows that SOri70 is either a brown dwarf or a planet. Brown dwarfs are "prevented suns". They are heavier than planets, but their mass is insufficient to ignite nuclear fusion.

If the object SOri70 really is a planet 36, 000 times as far as Jupiter or 180, 000 times as far as the Earth from the next star Sigma Orionis is like Jupiter or the Earth from the sun, then the researchers would have to seek an explanation of how it originated or drifted there. Alternatively, SOri70 could also be a brown dwarf who just happened to get in the line of sight between Earth and Sigma Orionis. The probability for the second alternative, the astronomers at 20 percent.

The decision between the two alternatives depends on a precise distance determination. Here astronomers hope for the help of the Hubble Space Telescope. The previous recordings were made with the Keck Observatory in Hawaii and with the William Herschel Telescope in the Canary Islands.

Besides Spanish astronomers and astronomers from the University of Hawaii, Joachim Eislöffel from the Thüringer Landessternwarte and Reinhold Mundt from the Max Planck Institute for Astronomy also participated in the discovery of SOri70. display

Axel Tilleman


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