JWST Detects Phosphine in Brown Dwarf Wolf 1130C
Why in the news
Astronomers using the James Webb Space Telescope (JWST) have found phosphine gas in the atmosphere of the brown dwarf Wolf 1130C. The result, published in Science on 2 October 2025, was widely reported in the first week of the month.
Key facts
- Phosphine was detected in the atmosphere of Wolf 1130C, a brown dwarf in the constellation Cygnus.
- This is described as the first JWST detection of phosphine in a brown dwarf.
- The object is a cold, metal-poor subdwarf brown dwarf roughly 61 light-years away.
- It orbits a pair made of an ultramassive white dwarf and a cool subdwarf star, forming a triple system.
- The measured abundance is about 0.100 parts per million, higher than in other brown dwarfs and exoplanets studied so far.
About brown dwarfs and phosphine
A brown dwarf has a mass between that of a planet and a star. It forms like a star but cannot sustain hydrogen fusion in its core, so it is often called a failed star. On Earth, phosphine is linked with living organisms, but brown dwarfs are not considered habitable, so the find is not a sign of life. Researchers suggest the gas may survive because of the object’s low-metal, oxygen-poor atmosphere, or that outbursts from its companion system enriched it with phosphorus. Phosphine was earlier reported in the atmosphere of Venus in 2020.
Exam angle
- Remember: JWST is the telescope; Wolf 1130C is the brown dwarf; the gas is phosphine.
- A brown dwarf is a sub-stellar object, heavier than a planet but unable to fuse hydrogen steadily.
- Phosphine here is not treated as evidence of habitability.