By studying data sent by the James Webb Space Telescope, astronomers have detected methane emissions coming from a brown dwarf, or «loser star» — previously thought to be not warm enough for this phenomenon.
«The presence of methane on giant planets and brown dwarfs is not surprising, but it usually does not glow», — says Jackie Faherty, team leader and senior education manager at the American Museum of Natural History.
Brown dwarfs are nicknamed losers because, despite being formed from a collapsing cloud of gas and dust like stars, they do not have enough mass to start the process of nuclear fusion of hydrogen into helium in their nuclei.
Faherty and colleagues observed a total of 12 brown dwarfs, and only one of them — W1935, located 47 million light-years from Earth — emitted methane. Further modeling showed that it also has the so-called «temperature inversion» — phenomenon, during which the planet’s atmosphere becomes colder at deeper levels. It is usually observed on planets orbiting stars that heat their atmosphere from the top down, but for W1935 it is quite unexpected — it is isolated and there is no external heat source.
«We were pleasantly shocked when the model accurately predicted the temperature inversion,» said team member and University of Hertfordshire scientist Ben Burningham. «But we also needed to figure out where the extra heat in the upper atmosphere was coming from».
To solve this mystery, the team studied the gas giants of the Solar System — Jupiter and Saturn. Both emit methane, have atmospheres that exhibit temperature inversion, and have their own auroras.
The main driver for this phenomenon is the solar wind — the flow of charged particles from the Sun. In W1935, there are no such «privileges» no privileges — so the researchers assume the presence of a hidden active moon near the dwarf.
The study was published on April 17 in the journal Nature.
Source: livescience