an international research team led by adam burgasser, a professor of astronomy and astrophysics at the university of california, san diego, announced in the international academic journal "science" that they have detected phosphine in the atmosphere of the ancient low-temperature brown dwarf "wolf 1130 c".
phosphine is a simple molecule composed of phosphorus and hydrogen. on earth, it may be produced by certain anaerobic microorganisms and industrial activities, and it is suggested that it may be a sign of life. within the solar system, phosphine also exists in the harsh atmospheres of giant gas planets such as jupiter and saturn, but its formation is believed to be related to non-biological high-temperature and high-pressure processes. however, there has never been a clear detection of phosphine in brown dwarfs or exoplanets before, and this discovery is unprecedented.
according to cnmo, the research object is the cold brown dwarf "wolf 1130 c" located in the cygnus constellation 54 light years away from earth, which orbits a dense binary star system composed of a red dwarf and a white dwarf.
professor adam burgasser said that by analyzing the high-precision infrared spectral data sent from the webb telescope, he discovered the unique absorption characteristics of phosphine in the atmosphere of wolf 1130 c. using advanced atmospheric inversion models, he concluded that the phosphine content in the brown dwarf's atmosphere is about one millionth.
co-author zhang zeng hua (an associate professor at nanjing university) pointed out that the "low metal content" (that is, the elemental content is much less than that of the sun) of wolf 1130 c may be changing the chemical composition of its atmosphere. in a normal oxygen-rich environment, phosphorus is more likely to combine with oxygen to form other molecules. however, in the oxygen-poor and hydrogen-rich atmosphere of this object, phosphorus can combine with abundant hydrogen to form phosphine and stabilize it.
another interesting hypothesis is that phosphorus may come from the white dwarf wolf 1130 b in the system. white dwarfs can absorb matter from their companion stars, which may trigger violent explosions called novae. although no recent explosions have been observed in this system, it is possible that ancient novae explosions that were not recorded released phosphorus-rich material into the system, which was eventually absorbed by the brown dwarf wolf 1130 c.
