Observations from the James Webb Space Telescope have revealed unusual compact objects that have puzzled astronomers. These objects combine the characteristics of stars and galaxies, which is why researchers have unofficially nicknamed them “platypuses”, similar to this animal. This discovery could shed light on galaxy formation processes in the early Universe, Space.com writes.
The objects appear as small points of light, but more detailed analysis shows that their structure and spectral characteristics are closer to those of galaxies.
“If we look at all the features separately, they seem incompatible – like the platypus. But together they form a complete picture,” explains astronomer Haojing Yan from the University of Missouri.
The results were presented at the annual meeting of the American Astronomical Society and published on the preprint server arXiv. Since the telescope's launch in 2021, it has repeatedly recorded objects of unknown nature, which prompted the team to systematically search for anomalies.
Scientists analyzed about 2,000 compact sources and eventually identified nine objects that turned out to be slightly larger than a point of light but at the same time retained a compact shape. Their light is more diffuse than that of stars, but not widespread enough for classical galaxies. The spectra of these objects show narrow emission lines characteristic of active star formation.
Initially, researchers considered the possibility that these were quasars – highly active galactic nuclei. However, these objects turned out to be too faint and their spectral lines were narrower than those of quasars.
This eliminates them from known types of quasars and may represent a previously unknown type of active galactic nucleus, Yan said.
Another theory is that platypuses are extremely young star-forming galaxies, less than 200 million years old. In this case, their compact size and “peaceful” star formation look especially unusual and suggest processes that astronomers have never observed before.
It is still unclear what type of object the scientists encountered. The team hopes to discover more examples in future observations.
