An exoplanet discovered in 2020 contains the coldest temperatures ever measured on a planetary body, according to scientists.
The planet, called WD 1856+534 b, is a gas giant exoplanet the size of nearly 14 Jupiters and nearly six times its mass, according to NASA. Recent observations from the James Webb Space Telescope, the most powerful telescope in space, suggest that the exoplanet’s average temperature is about -125 degrees Fahrenheit, making it the coldest planet ever detected, according to a paper published last week in arXiv, an open archive server.
Life can grow at temperatures as low as 5 degrees Fahrenheit, scientists say. However, few organisms can complete their life cycle at temperatures below 28.4 degrees Fahrenheit.
To date, emissions from no planets cooler than about 35.33 degrees Fahrenheit — a temperature comparable to Earth — have been directly detected, the researchers said.
WD 1856+534 b is a gas giant exoplanet that orbits a K-type star.
NASA
Astronomers used Webb’s sophisticated infrared optics and spectrometers to pinpoint characteristics of the exoplanet. By using the Direct Imaging Method, which consists of observing how much light is reflected from the surface or atmosphere of the exoplanet, scientists were able garner details about the planet’s formation and which biosignatures were present, such as oxygen, water and methane, according to the paper.
WD 1856+534 b is also the first transiting planet known to orbit a white dwarf star — the hot remnant of a star that has shed its outer layers after exhausting its nuclear fuels — the researchers said. Typically, a planet would become engulfed in the white dwarf star’s “forbidden zone” during the star’s red giant phase, according to the study.
It is likely twice the age of the Milky Way and orbits a K-type star — also known as orange dwarfs — in just 1.4 days, according to NASA. K-type stars are cooler and less massive than the sun.
Direct imaging of exoplanets can be difficult because of the overwhelming brightness coming from their host star, the authors said.
WD 1856+534 b is a gas giant exoplanet that orbits a K-type star.
NASA
However, advanced telescopes like Webb could eventually detect habitable planets outside our solar system, according to NASA.
NASA’s Habitable Worlds Observatory, a planned infrared and ultraviolet space telescope, will specifically target Earth-like planets around Sun-like stars when it launches in May 2027.
The researchers hope that further observations of WD 1856+534 b scheduled for 2025 will identify additional planets, according to the paper.