The James Webb Space Telescope (JWST) has made a groundbreaking discovery: for the first time in history, it has directly recorded the faint glow of an exoplanet that is colder than any other world known to science outside the Solar System. The object, named WD 1856+534 b, reveals the incredible possibilities of planetary survival even in the most extreme environments.
WD 1856+534 b was discovered back in 2020, it is twice as old as our Solar System. The exoplanet is similar in size to Jupiter, but almost six times more massive. Its average temperature is only -87°C. For comparison, the previous record holder was the +2°C exoplanet Epsilon India, which James Webb explored in 2023.
Such values make WD 1856+534 b the coldest exoplanet whose radiation has been directly recorded. The study data are published on the arXiv server.
Unique location
The most surprising thing is the location of the planet. It orbits around the white dwarf WD 1856+534, the dead core of a star that was once similar to the Sun. The distance between them is only 0.02 astronomical units, which is 50 times closer than Mercury is to the Sun. This region was considered a forbidden zone: during the death of the parent star, any planets here would have to be destroyed.
“WD 1856+534 b is the first intact planet discovered in such a region. This is evidence that the migration of planets to close orbits around white dwarfs is possible even in areas suitable for life,” the authors of the study emphasize.
Scientists hypothesize that WD 1856+534 b migrated to a white dwarf after the star passed the red giant phase. This means that even after catastrophic changes in the systems of dead luminaries, stable orbits for planets can exist.
New Horizons for James Webb
For a long time, WD 1856+534 b was considered a brown dwarf, an intermediate object between stars and planets. However, the JWST data confirmed it: its mass (up to 5.9 Jupiterian) and temperature unambiguously classify it as a gas giant. This makes it a full-fledged member of the catalog of exoplanets, with over 5,000 found in the last 30 years.
The discovery proves that James Webb is able to study even the coldest and dimmest objects. This finding not only expands the boundaries of our understanding of planetary systems, but also gives us hope: even in the dark corners of the Universe, there may be worlds waiting to be discovered.
We previously reported on how JWST discovered the best candidate for extraterrestrial life.
According to astrobiology.com
